2.1. Vesicles in the human developing brain in conditions of prenatal exposure to alcohol

The rapidly growing neuronal structures of the developing brain of the embryo and fetus are powered by a protein-rich fluid in the lumen of the neural tube. Subsequently, this mechanism becomes inadequate when their mass increases, and the task of delivering nutrients and removing metabolic products falls on blood vessels. It is extremely important to assess the degree of alcohol exposure to vasculogenesis of the developing brain fetus under the influence of prenatal alcohol exposure associated with maternal alcoholism [48].

As our studies showed, the vessels in the developing brain of embryos and fetuses for 8–9 weeks of development under normal conditions and in the presence of prenatal exposure to alcohol consisted only of capillaries with thin walls. Endotheliocytes and pericytes are presented on microphotographs, and the lumen of the vessels was open and contained formed blood elements. On the vessels, a basal membrane, consisting of a loose fibrillar material, was visible. Morphological differences in the development of vessels between the embryos of the control and main groups during the 8–9 weeks of pregnancy were not observed. In samples of the brain tissue of the fetuses from the main experimental group, the developmental period of 10 weeks of pregnancy identified erythrocyte stasis in some forming vessels (Figures 1 and 2). Our data show that vessels in the human brain start to differentiate into arteries and veins from 10 weeks of gestation (Figures 3 and 4). Brain vessels are differentiated into arterioles, capillaries and venules. Capillary basal membranes in the main experimental and control group were already clearly visible at 12 weeks of development (Figures 5 and 6). In both groups, we found that the apical surfaces of endotheliocytes remained smooth, with only occasional microvillus and no

Figure 3. In the center of the picture, the forming venule with the shaped elements of blood in the lumen of the vessel.

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Figure 4. Two arterioles are visible in the field of vision. Control group, embryo 10 weeks of development. Coloring

Figure 5. Ultrastructure of the basal membrane and capillary endothelium. The erythrocyte is visible in the lumen of the

vessel. Main group, fetus 11–12 weeks of development, 10,000.

Control group, embryo 10 weeks of development. Coloring methylene blue, 740.

methylene blue, 740.

Figure 1. Capillaries of the intermediate layer embryonic brain. Control group, embryo 10 weeks of development. Coloring methylene blue. 740.

Figure 2. Stasis of erythrocytes in the vessel between the exact layers. Main group, embryo 10 weeks of development. Coloring methylene blue. 740.

Molecular-Cellular Targets of the Pathogenetic Action of Ethanol in the Human Brain in Ontogenesis… http://dx.doi.org/10.5772/intechopen.73333 79

As our studies showed, the vessels in the developing brain of embryos and fetuses for 8–9 weeks of development under normal conditions and in the presence of prenatal exposure to alcohol consisted only of capillaries with thin walls. Endotheliocytes and pericytes are presented on microphotographs, and the lumen of the vessels was open and contained formed blood elements. On the vessels, a basal membrane, consisting of a loose fibrillar material, was visible. Morphological differences in the development of vessels between the embryos of the control and main groups during the 8–9 weeks of pregnancy were not observed. In samples of the brain tissue of the fetuses from the main experimental group, the developmental period of 10 weeks of pregnancy identified erythrocyte stasis in some forming vessels (Figures 1 and 2). Our data show that vessels in the human brain start to differentiate into arteries and veins from 10 weeks of gestation (Figures 3 and 4). Brain vessels are differentiated into arterioles, capillaries and venules. Capillary basal membranes in the main experimental and control group were already clearly visible at 12 weeks of development (Figures 5 and 6). In both groups, we found that the apical surfaces of endotheliocytes remained smooth, with only occasional microvillus and no

Figure 1. Capillaries of the intermediate layer embryonic brain. Control group, embryo 10 weeks of development.

Figure 2. Stasis of erythrocytes in the vessel between the exact layers. Main group, embryo 10 weeks of development.

Coloring methylene blue. 740.

78 Drug Addiction

Coloring methylene blue. 740.

Figure 3. In the center of the picture, the forming venule with the shaped elements of blood in the lumen of the vessel. Control group, embryo 10 weeks of development. Coloring methylene blue, 740.

Figure 4. Two arterioles are visible in the field of vision. Control group, embryo 10 weeks of development. Coloring methylene blue, 740.

Figure 5. Ultrastructure of the basal membrane and capillary endothelium. The erythrocyte is visible in the lumen of the vessel. Main group, fetus 11–12 weeks of development, 10,000.

significant protrusions of these cells into lumens, which remained open. We studied quantitative computer morphometric and established a series of characteristics of brain tissues samples in experimental group in comparison with control group (Table 1). Mean vessel cross-sectional areas and vessel perimeters in the main experimental group were significantly reduced by 11 weeks as compared with controls. The tendency for these measures to decrease in the experimental group compared with controls persisted at 12 weeks of development. Relative vessel cross-sectional area in samples of brain tissue from the main experimental group was greater than in control group. This measure was significantly greater in this group at 11 and 12 weeks of development. The number of vessels per unit area was significantly increased in the main experimental group at weeks 11 and 12 of fetal brain gestation as compared with control group.

vessels in the neocortical rudiment directly precedes the large scale migration of neuroblasts from the ventricular zone to the area of the cortical plate [22]. At 6–9 weeks of prenatal ontogenesis, developing intracerebral structures are not differentiated into arteries and veins, but have the structure of capillaries, which is consistent with our data. Endotheliocytes of intracerebral vessels are not fenestrated and contain small numbers of transport vesicles. At 8–9 weeks of gestation, vessels acquire basal membranes, which consist of a very loose fibrillar material with low electron density; there are also locations at which the endothelium makes direct contact with the intercellular space. At areas of contact between endotheliocytes and pericytes, interaction of the plasmalemmas of these cell types is seen in the form of mutual

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We have shown that the differentiation of vessels into capillaries, venules and arterioles in the developing brain of a person begins in 10–11 weeks of pregnancy. Computer morphometric analysis showed that the main effect of alcohol on the blood vessels in the brain of the fetuses was found during the development of 11 weeks of pregnancy. An increase in the number of vessels per unit cross-sectional area of the fetal brain was observed, while the average crosssectional area and perimeter of the vessels were reduced. Under conditions of prenatal alcohol influence, brain tissue undergoes hypoxia. Increase in the number of cerebral vessels per unit cross-sectional area is a compensatory adaptive mechanism in the development of this state. Thus, the influence of alcohol during pregnancy can significantly affect the dynamics of the cerebral circulation in the embryo and fetus, which is manifested by altering the vasculariza-

2.2. Cortical synaptogenesis in the human developing brain in conditions of prenatal

to establish the nature of this effect, we conducted the following studies.

As a lipotropic agent, ethanol, is able to change the basic physicochemical properties of cell membranes, which are reflected in the current synaptogenesis of the embryonic brain in order

In human embryonic brain in the early period—7–8th week of gestation, the desmosome-like contacts were represented as we observed. Contacting membranes are in their middle part of thickening, which both sides approach to each other, forming a fissure. In these places of the thickening, the membrane can be connected. Electron-dense material is in the field of adhesion. Contacts of this type are found between dendritic processes and neuronal cells. During the development of 9–10 weeks of pregnancy, these types of contacts are less frequent. Contacts with the presence of vesicular elements have been revealed. Synaptic vesicles were rounded and had a bright center, and the diameter of these vesicles was approximately 40 nm. The width of the synaptic space of immature synapses was approximately 20 nm. The length of the area of the sealing membrane reached 0.1–0.15 microns (Figure 7). In the transitional stage from synapse-like contacts to their true synaptic form, single synaptic vesicles were visualized near the presynaptic membrane. Such synapses are located mainly at the lower boundary of the intermediate layer of the cerebral cortex (Figures 8 and 9). They can already be considered

invagination [22].

tion of the developing human brain.

exposure to alcohol

functionally competent.

The first blood vessels in the human endbrain are seen at the start of week 7 of embryogenesis in the area of the ganglionic tubercle (the rudiment of the corpus striatum) and rather later in the rudiment of the neocortex (lateral wall of the lateral ventricle). The formation of blood

Figure 6. Basal membrane of the capillary without damage to the structure and a fragment of the cytoplasm of the endothelial cell. Main group, fetus 12 weeks of development, 45,000.


\* Significant difference with control, p < 0.05.

\*\*Significant difference compared with fetuses at 11 and 12 weeks of development, p < 0.01.

Table 1. Characteristics of brain vessels in normal conditions and in conditions of prenatal exposure to alcohol from week 10 to week 12 of intrauterine development (x sx).

vessels in the neocortical rudiment directly precedes the large scale migration of neuroblasts from the ventricular zone to the area of the cortical plate [22]. At 6–9 weeks of prenatal ontogenesis, developing intracerebral structures are not differentiated into arteries and veins, but have the structure of capillaries, which is consistent with our data. Endotheliocytes of intracerebral vessels are not fenestrated and contain small numbers of transport vesicles. At 8–9 weeks of gestation, vessels acquire basal membranes, which consist of a very loose fibrillar material with low electron density; there are also locations at which the endothelium makes direct contact with the intercellular space. At areas of contact between endotheliocytes and pericytes, interaction of the plasmalemmas of these cell types is seen in the form of mutual invagination [22].

significant protrusions of these cells into lumens, which remained open. We studied quantitative computer morphometric and established a series of characteristics of brain tissues samples in experimental group in comparison with control group (Table 1). Mean vessel cross-sectional areas and vessel perimeters in the main experimental group were significantly reduced by 11 weeks as compared with controls. The tendency for these measures to decrease in the experimental group compared with controls persisted at 12 weeks of development. Relative vessel cross-sectional area in samples of brain tissue from the main experimental group was greater than in control group. This measure was significantly greater in this group at 11 and 12 weeks of development. The number of vessels per unit area was significantly increased in the main experimental group at weeks 11 and 12 of fetal brain gestation as compared with control

The first blood vessels in the human endbrain are seen at the start of week 7 of embryogenesis in the area of the ganglionic tubercle (the rudiment of the corpus striatum) and rather later in the rudiment of the neocortex (lateral wall of the lateral ventricle). The formation of blood

Figure 6. Basal membrane of the capillary without damage to the structure and a fragment of the cytoplasm of the

Week 10 Week 11 Week 12 Week 10 Week 11 Week 12

49.08 2.61 51.82

340.58 35.87 292.20

0.000214 0.000078

3.07\*

1003\*

16.87\*

0.001137 0.000189\*

48.26 1.67

7.59 1.44\*

0.000624 0.000314\*

244.69 16.41

59.25 5.38

0.79 0.11 1.26 0.11 1.38 0.2 1.02 0.34 5.96

0.00023 0.000025

269.83 26.0

Measure Control group Experimental group

2.77

0.000189 0.000013

492.71 34.28

Table 1. Characteristics of brain vessels in normal conditions and in conditions of prenatal exposure to alcohol from

45.61 0.81\*\* 65.73

0.00017 0.000023

\*\*Significant difference compared with fetuses at 11 and 12 weeks of development, p < 0.01.

18.24

endothelial cell. Main group, fetus 12 weeks of development, 45,000.

Mean cross-sectional area of

Relative cross-sectional area of vessels in brain tissue, %

Number of vessels per 1 μm2 cross-sectional area of sections

Vessel perimeter, μm 349.44

Significant difference with control, p < 0.05.

week 10 to week 12 of intrauterine development (x sx).

vessels, μm2

\*

group.

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We have shown that the differentiation of vessels into capillaries, venules and arterioles in the developing brain of a person begins in 10–11 weeks of pregnancy. Computer morphometric analysis showed that the main effect of alcohol on the blood vessels in the brain of the fetuses was found during the development of 11 weeks of pregnancy. An increase in the number of vessels per unit cross-sectional area of the fetal brain was observed, while the average crosssectional area and perimeter of the vessels were reduced. Under conditions of prenatal alcohol influence, brain tissue undergoes hypoxia. Increase in the number of cerebral vessels per unit cross-sectional area is a compensatory adaptive mechanism in the development of this state.

Thus, the influence of alcohol during pregnancy can significantly affect the dynamics of the cerebral circulation in the embryo and fetus, which is manifested by altering the vascularization of the developing human brain.
