**5.2.2 NA metabolism**

104 Sexual Dysfunctions – Special Issue

has been reduced in groups with prenatal exposure of methylbenactyzine and ganglerone. Ratio indexes 5-HIAA/5-HT have been increased only in those groups in which decrease of

**Control** 0,244±0,018 0,976±0,068 0,637±0,037 0,608±0,035

**G-10** 0,228±0,026 1,120±0,061 0,470±0,023\* 0,578±0,041

**G-13** 0,194±0,022 1,192±0,078\* 0,461±0,030\* 0,636±0,028

**G-18** 0,340±0,020\* 1,134±0,062\* 0,540±0,026 0,587±0,032

**M-10** 0,344±0,022\* 1,240±0,059\* 0,378±0,033\* 0,538±0,039

**M-18** 0,402±0,031\* 1,188±0,069\* 0,490±0,041\* 0,550±0,039

Table 3. Turnover of DA and 5-HT neurotransmitters in hippocampus and hypothalamus at 2-month-old rat offspring exposed to methylbenactyzine or ganglerone at different periods

Research of neurotransmitters turnover in the hippocampus has shown that rats offspring subjected to exposure of cholinolytics have an enchancement of the turnover of the basic mediators, leading to decrease of concentration of these neurotransmitters in the hippocampus. Noted increase of DA turnover in the hippocampus of rats offspring prenatally subjected to exposure by methylbenactyzine (tab. 3) and significant increase of 5- HT turnover in the hippocampus of the offsprings, subjected to prenatal exposure both

The neurochemical status of DA in the hypothalamus of 2-month-old rats offsprings subjected to prenatal exposure of cholinolytics, was characterised by significant decrease of dopaminergic activity in relation to control (fig. 5). In comparison with the methylbenactyzine, prenatal exposure of the ganglerone, caused more appreciable remote

Concentration of the DA has been reduced in all groups - G10 - G18 (31,7 % - 36,9 %, р≤0,001) with maximally low value in G13 group. Among offsprings with prenatal exposure to methylbenactyzine significant decrease of DA noted only in M18 group (17,6 %, р≤0,05). Dynamics of DOPAC change in relation to control group was similar to dynamics of DA

significant 1,5 - 2 times decrease of DOPAC concentration in all groups was noted.

of prenatal development. (M ± m) \*-p < 0.05 compared with the control group

HIPPOCAMPUS HYPOTHALAMUS

**DA 5-HT DA 5-HT** 

mediator level became perceptible.

methylbenactyzine and ganglerone.

changes of DA level in the hypothalamus of these offsprings.

**5.2 Hypothalamus 5.2.1 DA metabolism** 

groups

The neurochemical status of NA in the hypothalamus was characterised by rising of processes of degradation of a mediator without enchancement of synthesis processes. In all studied groups both males and females had a decreased NA level and high MHPG content in the hypothalamus in comparison with control offsprings' grou. In comparison with methylbenactyzine, NA concentration in groups with prenatal exposure to ganglerone, has been reduced more considerably (in a greater degree in G10 group - decrease of the NA of 26,2 %, р≤0,001). The content of MHPG metabolite, on the contrary, has been raised in all groups in 1,5 - 2,5 times.

Fig. 5. Contents of dopamine (DA), noradrenaline (NA), and serotonin (5-HT) (ng/mg of wet tissue) in the hypothalamus in two-month-old rat offspring exposed to methylbenactyzine or ganglerone at different periods of prenatal development. \*p < 0.05 compared with the control group. For further details see caption to Fig. 1.

#### **5.2.3 5-HT metabolism**

Dynamics of 5-HT change in the hypothalamus was similar to other mediators – rats offsprings from G10 - G18 groups, where mediator level has been reduced in significant limens (accordingly, 24,3 % - 35,4 %, р≤0,001), had more radical changes in 5-HT content in G10 - G18 groups. In methylbenactyzine groups 5-HT concentration in the hypothalamus strengthened (in M10 group on 14,2 %, р≤0,05). 5-HIAA metabolite content in the hypothalamus of all the studied groups was similar to dynamics of the mediator.

The greatest changes of the neurotransmitters turnover in the hypothalamus have been detected concerning a DA both of rats males and females (tab. 1). DA turnover has considerably reduced in the males hypothalamus in all experimental groups in comparison with control group. The ratio index 5-HIAA/5-HT was more stable, except for G10 group of females which index was reduced. In the same group increase of 5-HT level at the stable content 5-HIAA was noticed that shows enchancement of serotoninergic synaptic activity in

Development of Male Sexual Function After Prenatal Modulation of Cholinergic System 107

within limbic system. Long-term effects of prenatal exposures of cholinolytics within amygdala nuclei have been brightly expressed. Study's results show significant decrease of DA, 5-HT and NA mediators content in the amygdala of the males prenatally subjected to exposure of gangleron, larger degree on 10-13 days of gestation (fig. 7). Prenatal exposure of M-cholinolytic methylbenactyzine had no strongly pronounced consequences on

development of neurotransmitter systems in the amygdala

**Control**

postnatal life.

Steingart et al., 2000).

**0,00**

**0,05**

**0,10**

**0,15**

**0,20**

**0,25**

**G-10 G-13 G-18**

\*

\*

**М-10**

**DA**

cholinergic system on sexual function.

\*

**М-13**

**М-18**

control group. For further details see caption to Fig. 1.

**Control**

**0,00**

**0,05**

**0,10**

**0,15**

**0,20**

**0,25**

**G-10**

**G-13**

Fig. 7. Contents of dopamine (DA), noradrenaline (NA), and serotonin (5-HT) (ng/mg of wet tissue) in the amygdala in two-month-old rat offspring exposed to methylbenactyzine or ganglerone at different periods of prenatal development. \*p < 0.05 compared with the

Changes of the neurotrasmitter status in the amygdala can affect functioning of other brain structures participating in regulation of sexual function, by means of neuronal connection of this structure with hippocampus and hypothalamus. It is shown that destruction of hypothalamo-amigdaloid connection, damage or irritation of the amygdala lead to neurohumoral alterations and sexual behavior abnormalities (Akmaev, 1993; Swanson, 1998; Dominguez, 2001). It is not excluded that optimization of integrative connections within limbic system and hypothalamus is extremely important concerning the effects of

Results of these researches show that pregnant females in "critical periods" of the embryo prenatal development exposure to M- and N-cholinoblockers can cause long-term changes in neurotransmitter systems activity in investigated structures of the rats brain in their

Exposure of M- and N-cholinolytics in the prenatal period leads to significant decrease of dopaminergic activity in the hippocampus and hypothalamus of rats offspring in comparison with control group. Results of various researches prove that defects of DA synaptic activity in the hippocampus at offspring can accompany to hippocampusassociated behavioral deficiencies at puberal individuals (Yanai, 1984; Smith, et al. 1986;

\* \*

**G-18**

**NA**

**М-10**

\*

\*

**М-13**

**М-18**

**Control**

**0,0**

**0,2**

**0,4**

**0,6**

**0,8**

**1,0**

**G-10**

**G-13**

\*

\*

**G-18**

\* \*

**5-HТ**

**М-10**

**М-13**

**\* -p<0,05**

**М-18**

\* \*

the hypothalamus. NA turnover in the hypothalamus of experimental groups was comparable with the data of control group though the mediator content and its metabolite has been reduced in all groups.

Sexual dimorphism in effects of prenatal exposure of M- and N-cholinolytics on dopaminergic system (fig.6) has been detected. In case of males offspring that were exposed to prenatal exposure of a ganglerone N-cholinolitics the decrease of DA concentration in the brain structures was noted; in case of rats females – the same reduction after prenatal exposure to M-cholinolytic methylbenactyzine.

Fig. 6. Sexual dimorphism according to dophamine concentration (ng/mg of wet tissue) in the hippocampus in two-month-old rat offspring exposed to methylbenactyzine or ganglerone at different periods of prenatal development. \*p<0.05 compared with the control group. Notations: - **♂, - ♀ -** simbols of the genetical sex of offspring, accordingly males and females.

#### **5.3 Amygdala**

For realization of adaptive and sexual behavior dopaminergic system of amygdala is also important. The amygdala initiates the organization of adequate behavior to the situation and by means of influence on the hypothalamus and vegetative excitatory system frames conforming hormonal and neurovegetative assurance to this behavior (Simonov, 1987). According to many researchers an amygdaloid complex is responsible for integration of emotional expressions, characteristic for sexual motivation (Newman, 1999; Dominguez, 2001).

Dynamics of neurotransmitters level in the amygdala was similar to the neurochemical status in the hippocampus that once again confirms their morphophysiologycal generality

the hypothalamus. NA turnover in the hypothalamus of experimental groups was comparable with the data of control group though the mediator content and its metabolite

Sexual dimorphism in effects of prenatal exposure of M- and N-cholinolytics on dopaminergic system (fig.6) has been detected. In case of males offspring that were exposed to prenatal exposure of a ganglerone N-cholinolitics the decrease of DA concentration in the brain structures was noted; in case of rats females – the same reduction after prenatal

has been reduced in all groups.

exposure to M-cholinolytic methylbenactyzine.

**G-10 G-13 G-18**

\*

**Control**

**0,0**

females.

2001).

**5.3 Amygdala** 

**1,0**

**2,0**

**3,0**

**4,0**

**5,0**

**М-10**

**DA - ♂**

\* \*

**М-18**

**Control**

**0,0**

Fig. 6. Sexual dimorphism according to dophamine concentration (ng/mg of wet tissue) in

ganglerone at different periods of prenatal development. \*p<0.05 compared with the control group. Notations: - **♂, - ♀ -** simbols of the genetical sex of offspring, accordingly males and

For realization of adaptive and sexual behavior dopaminergic system of amygdala is also important. The amygdala initiates the organization of adequate behavior to the situation and by means of influence on the hypothalamus and vegetative excitatory system frames conforming hormonal and neurovegetative assurance to this behavior (Simonov, 1987). According to many researchers an amygdaloid complex is responsible for integration of emotional expressions, characteristic for sexual motivation (Newman, 1999; Dominguez,

Dynamics of neurotransmitters level in the amygdala was similar to the neurochemical status in the hippocampus that once again confirms their morphophysiologycal generality

the hippocampus in two-month-old rat offspring exposed to methylbenactyzine or

**0,5**

**1,0**

**1,5**

**2,0**

**2,5**

**3,0**

**3,5**

**4,0**

**G-10**

**G-13**

**G-18**

**DA-♀**

**М-10**

**М-18**

\*

\*

\*

within limbic system. Long-term effects of prenatal exposures of cholinolytics within amygdala nuclei have been brightly expressed. Study's results show significant decrease of DA, 5-HT and NA mediators content in the amygdala of the males prenatally subjected to exposure of gangleron, larger degree on 10-13 days of gestation (fig. 7). Prenatal exposure of M-cholinolytic methylbenactyzine had no strongly pronounced consequences on development of neurotransmitter systems in the amygdala

Fig. 7. Contents of dopamine (DA), noradrenaline (NA), and serotonin (5-HT) (ng/mg of wet tissue) in the amygdala in two-month-old rat offspring exposed to methylbenactyzine or ganglerone at different periods of prenatal development. \*p < 0.05 compared with the control group. For further details see caption to Fig. 1.

Changes of the neurotrasmitter status in the amygdala can affect functioning of other brain structures participating in regulation of sexual function, by means of neuronal connection of this structure with hippocampus and hypothalamus. It is shown that destruction of hypothalamo-amigdaloid connection, damage or irritation of the amygdala lead to neurohumoral alterations and sexual behavior abnormalities (Akmaev, 1993; Swanson, 1998; Dominguez, 2001). It is not excluded that optimization of integrative connections within limbic system and hypothalamus is extremely important concerning the effects of cholinergic system on sexual function.

Results of these researches show that pregnant females in "critical periods" of the embryo prenatal development exposure to M- and N-cholinoblockers can cause long-term changes in neurotransmitter systems activity in investigated structures of the rats brain in their postnatal life.

Exposure of M- and N-cholinolytics in the prenatal period leads to significant decrease of dopaminergic activity in the hippocampus and hypothalamus of rats offspring in comparison with control group. Results of various researches prove that defects of DA synaptic activity in the hippocampus at offspring can accompany to hippocampusassociated behavioral deficiencies at puberal individuals (Yanai, 1984; Smith, et al. 1986; Steingart et al., 2000).

Development of Male Sexual Function After Prenatal Modulation of Cholinergic System 109

studies, which have demonstrated that administration of an N-cholinolytic to pregnant females at different periods of gestation leads to long-term changes in the development of

The most significant changes in the concentrations of DA, 5-HT, and NA and their metabolites in brain structures were seen after administration of ganglerone at 9–11 and 12– 14 days of gestation, which was apparent as reductions in the synaptic activities of these brain neurotransmitter systems, particularly dopaminergic activity in the hippocampus and hypothalamus in two-month-old offspring of rats as compared with controls. Although 20 day embryos showed an increase in DA levels in response to administration of ganglerone at 12–14 days of gestation, this requires further investigation. It can be suggested that like nicotine, ganglerone, blocking N-cholinergic receptors, induced impairments to the formation and establishment of network systems in the developing embryonic brain, which promoted stable decreases in the synaptic activity of the transmitter systems of interest in the hippocampus and hypothalamus of twomonth-old offspring rats as compared with controls. This imbalance in neurotransmitter activity in brain limbic structures in twomonth-old offspring is a long-term neurochemical effect of prenatal treatment with

The neurotransmitter DA plays an important role in activating the sexual behavior in male rats; DA depletion in brain structures involved in regulating the behavioral states of body facilitates reductions in sexual activity (Gladkova, 2000; Mas et al., 1987; Pfaus & Phillips, 1991). Lesioning of different dopaminergic projections induces different behavioral syndromes depending on which part of the CNS is lesioned (Carey & Schwarting, 1986; Simon et al., 1986); in particular, damage to the dopaminergic projections of limbic

The noradrenergic and serotoninergic systems of the brain are also involved in regulating hormone-dependent behavioral states, including sexual behavior (Naumenko et al., 1983; Lenahan et al., 1986; Smeets & Reiner, 1994). Affecting the secretion of gonadoliberin in the hypothalamic nuclei, NA and 5-HT act on α2,β2-adrenoreceptors and 5-HT1,2 serotonin receptors to take part in the central regulation of the endocrine system of the male body and,

Thus, prenatal modulation of N-cholinergic brain mechanisms with ganglerone can alter the activities of DA, NA, and 5-HT systems, which are directly involved in regulating motivation and components of coitus in adult offspring. We believe that this mechanism is the main cause of long-term behavioral impairments in pubescent offspring subjected to prenatal exposure to cholinolytics. The prenatal effects of cholinolytics on sexual function in offspring represent a paradox, which is that in relation to the cholinergic system, sexual activity in adult males is regulated mainly by M-cholinolytic mechanisms, while during the

Another mechanism mediating the long-term actions of cholinolytics on sexual function in offspring consists of the involvement of endocrine factors. Considering the role of the central and peripheral compartments of the nervous system in controlling the hypothamalohypophyseal-gonadal system in males, it can be suggested that prenatal administration of cholinolytics to pregnant females might also have long-term consequences in relation to the

The results obtained from endocrine studies supported the occurrence of endocrine impairments in pubescent offspring (Fig. 8). A significant reduction in testosterone levels was seen in offspring subjected to prenatal exposure to ganglerone at different periods of

prenatal period, these are more dependent on the activity of N-cholinergic system.

brain neurotransmitter systems in 20-day embryos and two-month offspring of rats.

ganglerone, which in turn may facilitate sexual dysfunction in fertile males.

structures leads to impairments in male sexual function (Hull et al., 1984).

thus, in controlling male sexual function.

endocrine system of offspring.

The prenatal nicotine exposure which is exogenous ligand of N-cholinergic receptor leads to nonperishable change of activity of the basic neurotransmitter systems in brain structures in a postnatal period. The decrease of DA concentration in the brain structures at males has been detected at offspring which were subjected to prenatal exposure of N-cholinolytic ganglerone, and at females - to mainly prenatal exposure of M-cholinolytic methylbenactyzine (Genedani et al., 1983; Ribary, 1985; Lichtensteiger et al., 1988; Lichtensteiger & Schlumpf, 1993; Muneoka et al., 1997).

In spite of various mechanisms of M- and N-cholinolytics action in the organism, the longterm effects of these drugs on the basic transmitter systems development in offspring are basically the same, namely inhibiting a metabolism of these neurotransmitters. Prenatal exposure of selective M- and N-cholinolytics, like other chemical drugs and ecological toxicants with cholinergic properties, causes the long-term changes in programming of neurotransmitter functions in 2-month's offspring which, in turn, can participate in the development of neuro-behavioral anomalies, appetent and affective disturbances at puberal individuals (Lauder, 1985; Turlejski, 1996; Levitt et al., 1997; Dreyfus, 1998; Azmitia, 2001).

Thus, the prenatal exposure of M- and N-cholinolytics to pregnant females produces longterm neurochemical changes in the development of brain neuromediatory systems. In the studied brain structures, both males and females, exposure to prenatal cholinolytics, significant decrease of DA, 5-HT, NA concentrations and change of level of their metabolites were marked. Prenatal exposure to ganglerone N-cholinolytics to pregnant females on 9-19 gestational days exerts most appreciable long-term effect on neurotransmitter development, which leads to reduction of dopaminergic, noradrenergic and serotonergic activity in the hippocampus and hypothalamus of 2-month-old rats progenies in comparison with control group. Is was noted that prenatal exposure of cholinolytics on DA concentration in the brain structures at 2-month-old rats progenies causes sexual dimorphism. These results indicate that exposure to M- and N-cholinolytics during the critical periods of prenatal development (9-11 and 12-14 gestational days) results in long-term changes in development of neuromediatory systems in the brain structure, which participate in regulation of behavioral and neuroendocrinal functions of rats offsprings.

#### **6. Endocrinological consequences of prenatal exposure to N-cholinolytics in the rats offspring's**

The involvement of N-cholinergic mechanisms in behavioral impairments in male offspring is associated with the properties of N-cholinoreceptors, which are involved in the regulation of the catecholaminergic system of the CNS. N-cholinergic neurons are connected to different types of neurons in the brain, and activation of N-cholinoreceptors by endogenous (acetylcholine) or exogenous (nicotine) ligands modulates the release of the transmitters DA, NA, and 5-HT, depending on the type of cell (Retana, 1993; McGehee et al., 1995). Nicotinic receptors are abundant in the subcortical areas of the brain during early fetal development (Lisk & Greemvald, 1983), so embryonic exposure to nicotine damages noradrenergic and dopaminergic synaptic transmission in the brain (Navarro et al., 1988; Seidler et al., 1992).

It follows from this that the mechanism of prenatal exposure to the N-cholinolytic ganglerone on sexual function in offspring may be mediated by modulation of brain transmitter systems, including DA, NA, and 5-HT systems, which indirectly regulate the processes of motivation and components of coitus (Bitran & Hull, 1987; Gladkova, 2000; Mas et al., 1987; Pfaus & Phillips, 1991). This thesis is supported by results from neurochemical

The prenatal nicotine exposure which is exogenous ligand of N-cholinergic receptor leads to nonperishable change of activity of the basic neurotransmitter systems in brain structures in a postnatal period. The decrease of DA concentration in the brain structures at males has been detected at offspring which were subjected to prenatal exposure of N-cholinolytic ganglerone, and at females - to mainly prenatal exposure of M-cholinolytic methylbenactyzine (Genedani et al., 1983; Ribary, 1985; Lichtensteiger et al., 1988;

In spite of various mechanisms of M- and N-cholinolytics action in the organism, the longterm effects of these drugs on the basic transmitter systems development in offspring are basically the same, namely inhibiting a metabolism of these neurotransmitters. Prenatal exposure of selective M- and N-cholinolytics, like other chemical drugs and ecological toxicants with cholinergic properties, causes the long-term changes in programming of neurotransmitter functions in 2-month's offspring which, in turn, can participate in the development of neuro-behavioral anomalies, appetent and affective disturbances at puberal individuals (Lauder, 1985; Turlejski, 1996; Levitt et al., 1997; Dreyfus, 1998; Azmitia, 2001). Thus, the prenatal exposure of M- and N-cholinolytics to pregnant females produces longterm neurochemical changes in the development of brain neuromediatory systems. In the studied brain structures, both males and females, exposure to prenatal cholinolytics, significant decrease of DA, 5-HT, NA concentrations and change of level of their metabolites were marked. Prenatal exposure to ganglerone N-cholinolytics to pregnant females on 9-19 gestational days exerts most appreciable long-term effect on neurotransmitter development, which leads to reduction of dopaminergic, noradrenergic and serotonergic activity in the hippocampus and hypothalamus of 2-month-old rats progenies in comparison with control group. Is was noted that prenatal exposure of cholinolytics on DA concentration in the brain structures at 2-month-old rats progenies causes sexual dimorphism. These results indicate that exposure to M- and N-cholinolytics during the critical periods of prenatal development (9-11 and 12-14 gestational days) results in long-term changes in development of neuromediatory systems in the brain structure, which participate in regulation of behavioral

**6. Endocrinological consequences of prenatal exposure to N-cholinolytics in** 

The involvement of N-cholinergic mechanisms in behavioral impairments in male offspring is associated with the properties of N-cholinoreceptors, which are involved in the regulation of the catecholaminergic system of the CNS. N-cholinergic neurons are connected to different types of neurons in the brain, and activation of N-cholinoreceptors by endogenous (acetylcholine) or exogenous (nicotine) ligands modulates the release of the transmitters DA, NA, and 5-HT, depending on the type of cell (Retana, 1993; McGehee et al., 1995). Nicotinic receptors are abundant in the subcortical areas of the brain during early fetal development (Lisk & Greemvald, 1983), so embryonic exposure to nicotine damages noradrenergic and dopaminergic synaptic transmission in the brain (Navarro et al., 1988; Seidler et al., 1992). It follows from this that the mechanism of prenatal exposure to the N-cholinolytic ganglerone on sexual function in offspring may be mediated by modulation of brain transmitter systems, including DA, NA, and 5-HT systems, which indirectly regulate the processes of motivation and components of coitus (Bitran & Hull, 1987; Gladkova, 2000; Mas et al., 1987; Pfaus & Phillips, 1991). This thesis is supported by results from neurochemical

Lichtensteiger & Schlumpf, 1993; Muneoka et al., 1997).

and neuroendocrinal functions of rats offsprings.

**the rats offspring's** 

studies, which have demonstrated that administration of an N-cholinolytic to pregnant females at different periods of gestation leads to long-term changes in the development of brain neurotransmitter systems in 20-day embryos and two-month offspring of rats.

The most significant changes in the concentrations of DA, 5-HT, and NA and their metabolites in brain structures were seen after administration of ganglerone at 9–11 and 12– 14 days of gestation, which was apparent as reductions in the synaptic activities of these brain neurotransmitter systems, particularly dopaminergic activity in the hippocampus and hypothalamus in two-month-old offspring of rats as compared with controls. Although 20 day embryos showed an increase in DA levels in response to administration of ganglerone at 12–14 days of gestation, this requires further investigation. It can be suggested that like nicotine, ganglerone, blocking N-cholinergic receptors, induced impairments to the formation and establishment of network systems in the developing embryonic brain, which promoted stable decreases in the synaptic activity of the transmitter systems of interest in the hippocampus and hypothalamus of twomonth-old offspring rats as compared with controls. This imbalance in neurotransmitter activity in brain limbic structures in twomonth-old offspring is a long-term neurochemical effect of prenatal treatment with ganglerone, which in turn may facilitate sexual dysfunction in fertile males.

The neurotransmitter DA plays an important role in activating the sexual behavior in male rats; DA depletion in brain structures involved in regulating the behavioral states of body facilitates reductions in sexual activity (Gladkova, 2000; Mas et al., 1987; Pfaus & Phillips, 1991). Lesioning of different dopaminergic projections induces different behavioral syndromes depending on which part of the CNS is lesioned (Carey & Schwarting, 1986; Simon et al., 1986); in particular, damage to the dopaminergic projections of limbic structures leads to impairments in male sexual function (Hull et al., 1984).

The noradrenergic and serotoninergic systems of the brain are also involved in regulating hormone-dependent behavioral states, including sexual behavior (Naumenko et al., 1983; Lenahan et al., 1986; Smeets & Reiner, 1994). Affecting the secretion of gonadoliberin in the hypothalamic nuclei, NA and 5-HT act on α2,β2-adrenoreceptors and 5-HT1,2 serotonin receptors to take part in the central regulation of the endocrine system of the male body and, thus, in controlling male sexual function.

Thus, prenatal modulation of N-cholinergic brain mechanisms with ganglerone can alter the activities of DA, NA, and 5-HT systems, which are directly involved in regulating motivation and components of coitus in adult offspring. We believe that this mechanism is the main cause of long-term behavioral impairments in pubescent offspring subjected to prenatal exposure to cholinolytics. The prenatal effects of cholinolytics on sexual function in offspring represent a paradox, which is that in relation to the cholinergic system, sexual activity in adult males is regulated mainly by M-cholinolytic mechanisms, while during the prenatal period, these are more dependent on the activity of N-cholinergic system.

Another mechanism mediating the long-term actions of cholinolytics on sexual function in offspring consists of the involvement of endocrine factors. Considering the role of the central and peripheral compartments of the nervous system in controlling the hypothamalohypophyseal-gonadal system in males, it can be suggested that prenatal administration of cholinolytics to pregnant females might also have long-term consequences in relation to the endocrine system of offspring.

The results obtained from endocrine studies supported the occurrence of endocrine impairments in pubescent offspring (Fig. 8). A significant reduction in testosterone levels was seen in offspring subjected to prenatal exposure to ganglerone at different periods of

Development of Male Sexual Function After Prenatal Modulation of Cholinergic System 111

Experimental researches have shown that the rats males subjected to prenatal exposure of a ganglerone and characterized by low sexual activity, have appeared sensitive to effects of

**Intromissions** 

**(n)** 

**Control** 17,1 ±3,1 26,0 ±9,0 11,4 ±2,1 53,9 ±16,0 0,90 ±0,17 278,8 ±53,0 403,5 ±29,1

**latency of** 

**1 hour** 29,6 ±1,3\* 13,3 ±2,0\* 17,1 ±2,9\* 29,5 ±3,2\* 1,83 ±0,22\* 184,4 ±36,4\* 313,4 ±41,2\*

**7 days** 14,1 ±2,1 21,9 ± 3,8 10,1 ±2,9 42,3 ±7,8 1,04 ±0,18 267,0 ±41,5 394,1 ±54,3

**1 hour** 24,6 ±2,8\* 12,4 ±2,5\* 18,8 ±3,1\* 28,7 ±4,7\* 1,55 ±0,19\* 198,3 ±36,0\* 329,1 ±39,5\*

**7 days** 16,6 ±2,1 30,5 ± 4,1 12,0 ± 2,4 55,8 ±7,2 1,10 ±0,17 288,2 ±41,5 386,0 ±50,6

**1 hour** 31,6 ±4,4\* 8,30 ±2,3\* 21,2 ±3,8\* 23,3 ±5,9\* 1,97 ±0,30\* 166,2 ±32,1\* 320,5 ±52,6\*

**7 days** 19,9 ±3,0 24,2 ± 3,6 12,2 ±1,2 45,4 ±6,7 1,09 ±0,18 237,3 ±38,2 425,0 ±57,9

Note: The sexual activity is recorded in 1 hour after an injection and for 7 days of an afteraction of

exposure to ganglerone on 12-14 day of gestation (G13 group) before and after application of

Cholinomimetic drug arecoline (2 mg/kg), galantamine with a ganglerone (accordingly, 1mg/kg and 5 mg/kg) and agonist of D1,D2-dopaminergic receptors apomorphinum (1 mg/kg) considerably enhanced sexual function. Components of sexual function - mounts, intromissions and ejaculations after pharmacological correction were high enough though did not reach in certain cases indexes of sexual behavior of control offspring. On the contrary, time components of a sexual behavior specified about sufficient high degree of

In spite of significant enchancement of the sexual function, the obtained data have shown that correction of sexual activity descended only during the period of drugs action - within 1 days. For 7 day after introduction of stimulating drugs quantitative and qualitative

Table 4. Parameters of sexual behavior in the mature male rats subjected to prenatal

**intromission** 

**(sec)** 

**Ejaculation** 

**(n)** 

**latency of** 

**ejaculation** 

**(sec)** 

**Interejaculatory** 

**interval (sec)** 

cholinergic and dopaminergic (tab. 4).

**Mounts** 

**(n)** 

**latency of mount** 

**(sec)** 

**G13 group** 

**Arecoline** 

**Galantamine + Ganglerone** 

**Apomorphinum** 

the agents. (M±m).

drugs.

\*-p < 0.05 compared with control group.

sexual activation, including motivation enchancement.

characteristics of rats male sexual behavior were reverted on initial level.

gestation, with lowest values seen in the offspring of group G13 (2.4-fold decrease). There was also a significant decrease in the testosterone level in offspring subjected to prenatal exposure to methylbenactyzine in group M18. The LH and FSH levels in the blood of all groups were increased.

The hormonal-motivational component of sexual behavior of male rats is known to controlled at the central level by testosterone, which is metabolized to estradiol, while ejaculation is controlled at the peripheral level by the non-aromatized dihydrotestosterone and only partially by testosterone (Lisk, 1983). Low testosterone levels in G10–G13 offspring could therefore facilitate alterations in both the central motivational and the peripheral ejaculatory components of sexual behavior. The reduced testosterone level in G10–G18 offspring correlated with low sexual activity and, conversely, numbers of the sexually more active males of groups M10–M18 had higher testosterone levels.

Fig. 8. Serum Testosterone, LH and FSH levels in two-month-old rat offspring exposed to ganglerone or methylbenactyzine at different periods of prenatal development. \*p < 0.05 compared with control group. For further details see caption to Fig. 1.

Thus, along with neuronal factors, changes in the hormonal background probably represent a further cause of impairments to sexual functions in offspring subjected to prenatal exposure to central cholinolytics. Reproductive impairments induced by damage to the neuroendocrine and neurotransmitter systems during the fetal period of ontogenesis due to prenatal exposure to cholinolytics may in later life become the cause of impairments to the ability of males to mate and produce offspring.
