**5. The long-term neurochemical effects of prenatal exposure to selective Mand N-cholinolytics**

Prenatal exposure of some neurotropic agents results not only in disturbances of a proliferation and a differentiation of embryos brain neurones, but also causes the remote disorders of development of synaptic function of brain neurones, disturbance of ontogenetic development of the brain basic neurotransmitter systems in the postnatal period (Robinson, 2000; Icenogle, 2004). Studying of development of the central monoaminergic systems of the brain structures participating in regulation neuroendocrinal and behavioral functions of organism of the rats offspring aged 2 months, therefore is obviously important.

The investigations showed that the prenatal exposure of M- and N-cholinolytics to pregnant females produces long-term neurochemical changes in development of brain neuromediatory systems. In the investigated of brain structures, both at males, and at females of rats progenies, exposure to prenatal cholinolytics, significant decrease of DA, 5- HT, NA concentrations and change of level of their metabolites is marked.

The analysis of the received data has shown that prenatal introduction of cholinolytics with selective M- and N-cholinergic activity (methylbenactyzine and ganglerone) to pregnant females leads to the remote changes of brain monoaminergic system activity (DA, NA and 5-HT) of 2-month-old rats offspring.

#### **5.1 Hippocampus**

Rats offrspins that were subjected to prenatal exposure of a ganglerone had a decreased in 1,5 - 2,5 times (р≤0,001) DA level in the hippocampus. The greatest falling of DA level noted in group with ganglerone exposure on 9-11 days of a gestation (fig. 4). Though in groups with prenatal exposure of a methylbenactyzine DA content in a hippocampus has not changed. In group M10 among offsprings with a prenatal exposition of a methylbenactyzine was noted a tendency to augmentation.

Dynamics of DOPAC in the studied groups in comparison to control groups was opposite to DA content - substantial growth of DOPAC concentration in groups G10 and G13 (accordingly on 21,7 % and 26,3 %, р≤0,001) was noted. The neurochemical status in hippocampus of the males prenatally exposured to cholinolytics was characterized by serious decrease of DA concentration and change of its metabolite level in comparison with control offsprings.

Fig. 4. Contents of dopamine (DA), noradrenaline (NA), and serotonine (5-HT) (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. For further details see caption to Fig. 1.

## **5.1.1 NA metabolism**

102 Sexual Dysfunctions – Special Issue

**groups n DOPAC -♂ 5-HIAA -♂ DOPAC -♀ 5-HIAA -♀**

**Control 63** 0,0121+0,0008 0,1262+0,0030 0,0150+0,0011 0,1292+0,0031

**G10 33** 0,0132+0,0030 0,1139+0,0032 0,0054+0,0006\* 0,1049+0,0034\*

**G13 16** 0,0110+0,0013 0,1390+0,0042 0,0090+0,0009\* 0,1280+0,0045

**G18 36** 0,0054+0,0004\* 0,1278+0,0026 0,0102+0,0006\* 0,1112+0,0019

**M10 41** 0,0085+0,0008\* 0,1156+0,0028 0,0115+0,0008\* 0,1116+0,0030

**M13 47** 0,0119+0,0004 0,1000+0,0025\* 0,0097+0,0005\* 0,1034+0,0030\*

**M18 32** 0,0090+0,0009\* 0,1061+0,0032 0,0051+0,0003\* 0,1074+0,0025\*

Table 2. Content of DOPAC and 5-HIAA in the brains of 20-day rat embryos. (M ± m) Notations: - **♂, - ♀ -** simbols of the genetical sex of offspring, accordingly males and females.

organism of the rats offspring aged 2 months, therefore is obviously important.

HT, NA concentrations and change of level of their metabolites is marked.

**5. The long-term neurochemical effects of prenatal exposure to selective M-**

Prenatal exposure of some neurotropic agents results not only in disturbances of a proliferation and a differentiation of embryos brain neurones, but also causes the remote disorders of development of synaptic function of brain neurones, disturbance of ontogenetic development of the brain basic neurotransmitter systems in the postnatal period (Robinson, 2000; Icenogle, 2004). Studying of development of the central monoaminergic systems of the brain structures participating in regulation neuroendocrinal and behavioral functions of

The investigations showed that the prenatal exposure of M- and N-cholinolytics to pregnant females produces long-term neurochemical changes in development of brain neuromediatory systems. In the investigated of brain structures, both at males, and at females of rats progenies, exposure to prenatal cholinolytics, significant decrease of DA, 5-

The analysis of the received data has shown that prenatal introduction of cholinolytics with selective M- and N-cholinergic activity (methylbenactyzine and ganglerone) to pregnant females leads to the remote changes of brain monoaminergic system activity (DA, NA and

Rats offrspins that were subjected to prenatal exposure of a ganglerone had a decreased in 1,5 - 2,5 times (р≤0,001) DA level in the hippocampus. The greatest falling of DA level noted

\*-p < 0.05 compared with control group.

5-HT) of 2-month-old rats offspring.

**5.1 Hippocampus** 

**and N-cholinolytics** 

The obtained data showed decrease of the NA content and increase of its metabolite MHPG (3-methoxy-4-hydroxyphenylethylene glycol) concentration that led to NA synaptic activity decrease. In case of rats males decrease of NA concentration in hippocampus was noted only in two groups subjected to prenatal exposure of a ganglerone in early periods of gestation - G10 and G13 (accordingly 66,6 % and 70,0 %, р≤0,001). Thus the content of a noradrenaline metabolite of MHPG has been enlarged in all investigated groups in 1,5 - 2,0 times*.* 

#### **5.1.2 5-HT metabolism**

Unlike other neurotransmitters 5-HT level in the hippocampus has been reduced in all groups of both gender in comparison with control offsprings group. Males offsprings had significant reduction of 5-HT content in the range from 19,7 % (р≤0,01) - in G10 and to 32,6 % (р≤0,001) in M18 group. The serotonin metabolite level 5-HIAA in the hippocampus also

Development of Male Sexual Function After Prenatal Modulation of Cholinergic System 105

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

**G-10**

Fig. 5. Contents of dopamine (DA), noradrenaline (NA), and serotonin (5-HT) (ng/mg of

methylbenactyzine or ganglerone at different periods of prenatal development. \*p < 0.05

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

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

\*

\*

\*

**Control**

**0,0 0,2 0,4 0,6 0,8 1,0 1,2 1,4 1,6 1,8 2,0**

wet tissue) in the hypothalamus in two-month-old rat offspring exposed to

compared with the control group. For further details see caption to Fig. 1.

hypothalamus of all the studied groups was similar to dynamics of the mediator.

**G-13**

**G-18**

**М**

**-10**

**М-18**

\*

**G-10**

**Control**

**NA 5-HТ**

**G-13**

\* \*

**G-18**

\*

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

**М-10**

**М-18**

**5.2.2 NA metabolism** 

groups in 1,5 - 2,5 times.

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

**\*** \* \*

**Control**

**5.2.3 5-HT metabolism** 

**0,00**

**0,05**

**0,10**

**0,15**

**0,20**

**0,25**

**0,30**

**0,35**

**М-10**

**DA**

**М-18**

\*


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 mediator level became perceptible.

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

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 methylbenactyzine and ganglerone.

### **5.2 Hypothalamus**

#### **5.2.1 DA metabolism**

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 changes of DA level in the hypothalamus of these offsprings.

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.
