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Sympathetic innervation of the stomach was studied in rats by the method of retrograde axon transport of Fast Blue in postnatal ontogenesis. The number of labeled neurons increased in the first 10 days of life and then did not change until the senescence. All labeled neurons innervating the stomach contain the catecholamine synthesis enzyme, tyrosine hydroxylase. The proportion of labeled neuropeptide Y-immunopositive neurons did not change in the development, the percentage of labeled calbindin-immunoreactive neurons decreased in the first month of life.

Sympathetic innervation of the stomach is carried out by the prevertebral ganglia of the solar plexus. The localization and neurochemical composition of neurons innervating the stomach in postnatal ontogenesis in rats was studied using the method of retrograde axon transport of Fast Blue. In all animals, the celiac ganglia had more labeled neurons compared to the superior mesenteric ganglion. The number of labeled neurons increased in the first 10 days of life and then did not change until the senescence. All labeled neurons innervating the stomach contain the catecholamine synthesis enzyme, tyrosine hydroxylase. The proportion of labeled neuropeptide Y-immunopositive neurons did not change in the development, the percentage of labeled calbindin-immunoreactive neurons decreased in the first month of life.Симпатическая иннервация желудка осуществляется превертебральными узлами солнечного сплетения. Методом ретроградного аксонного транспорта быстрого голубого (Fast Blue) исследовали локализацию и нейрохимический состав нейронов, иннервирующих желудок в постнатальном онтогенезе у крыс. У всех животных в чревных узлах выявляли больше нейронов, содержащих метку, по сравнению с краниальным брыжеечным узлом. Количество меченых нейронов возрастало в первые 10 сут жизни и далее не изменялось вплоть до старости. Все меченые нейроны, иннервирующие желудок, содержат фермент синтеза катехоламинов — тирозингидроксилазу. Доля меченых нейропептид-Y-иммунопозитивных нейронов не менялась в онтогенезе, доля меченых кальбиндин-иммунореактивных нейронов снижалась в первый месяц жизни.

Expression of neuronal NO synthase in the sympathetic cranial cervical ganglion and stellate ganglion in rats during postnatal ontogeny was studied by immunohistochemistry and Western blotting. In the sympathetic ganglia, neuronal NO synthase-immunoreactive neurons were absent in all rats. In the stellate and cranial cervical ganglia, the expression of neuronal NO synthase and the density of immunoreactive fibers increased in early postnatal ontogeny from the moment of birth to the age of 30 days and then decreased. Thus, we observed heterochroneous expression of neuronal NOS in the preganglionic somata in the spinal cord and in the preganglionic fibers in the sympathetic ganglia during ontogeny.

Sensory neurons represent various groups of neurons differ on their morphological, immunohistochemical and receptor characteristics. The most of large neurons with myelinated Adelta fibers contain neurofilament 200 kD (NF200), some small afferent neurons can bind the isolectin B4 (IB4). Also, sensory neurons may include different types of tyrosine kinases (trkA, B and C) and neurotransmitters. Neuropeptides are generally located in small and medium-sized neurons. The proportion of neurons which contain trkA decreases and the percentage of NF200-, IB4-,substance P- and CGRP-positive neurons increases during the early development. Development of different types of sensory neurons fulfill under control of neurotrophins.

Morphological features of calcitonin gene-related peptide (CGRP)-immunoreactive neurons were studied in the sensory ganglia of the vagus and thoracic nerves in 3-, 10-, 20-, 30-, 60-, 90-, and 120-day-old rats under conditions of chemically-induced deafferentation. We found that, in rats, CGRP-containing neurons appeared in both ganglia immediately after they were born and their number decreased with aging. Most of CGRP-immunoreactive neurons were small in size, i.e., up to 600 microm2. Administration of capsaicin modified age-related changes in the number of CGRP-immunopositive neurons. In the thoracic nerve ganglion, the mean square of these cells and their number substantially decreased, whereas, in the vagus nerve ganglion, positive cells were not observed.

Morphological features of the neurons containing neurofilaments with molecular mass of 200 kD (NF200+), were studied in the sensory ganglia of thoracic and lumbar spinal nerves in rats (n = 80) during the first year of their life. Capsaicin treatment (150 mg/kg) of the newborn animals resulted in the change of age dynamics of NF200+ neurons. This was reflected by a reduction of NF200+ neuron numbers and their cross-sectional areas in both ganglia. Segmental differences included greater reduction of NF200+ neuron number in the sensory ganglion of lumbar spinal nerve in both early and late developmental periods.

Afferent neurons containing substance P (SP) were studied immunohistochemically in the sensory ganglion of the spinal nerve in 30 rats aged 10-90 days. The results obtained indicated that SP-immunoreactive neurons are present in thesel ganglia from the moment of birth. During the development, the percentage of SP-containing neurons decreased till day 10. SP-immunoreactive neurons were represented by the cells of very small or small size.

Neurons of cranial cervical, stellate and celiac sympathetic ganglia containing calbindin (CALB) were studied in rats (n = 60) aged 3-90 days using immunohistochemical method. The results obtained indicate that the largest population of CALB-immunopositive neurons was located in the stellate ganglion. The proportion of CALB-containing neurons in sympathetic para- and prevertebral ganglia decreased during the development. Final formation of CALB-immunopositive group of neurons was observed by the end of the first month of life.

Expression of vanilloid receptors in sympathetic and afferent ganglionic neurons was studied in rats of different ages (newborn, 10-day old, 20-day old, 30-day old, 60-, 180-day old) using immunohistochemical methods. The results obtained indicate that the majority of the afferent neurons in the nodose ganglion of vagus nerve (GNVN) and in the spinal ganglia (SG) were TRPV1-positive from birth onwards. The percentage of neurons containing TRPVT receptors in SG slightly increased with age up to 30 days postnatally. In the GNVN, the percentage of TRPV1-positive neurons was higher in comparison with the SG in all age groups. The vast majority of the sympathetic neurons were TRPV1-positive from birth onwards, and the percentage of TRPV1-immunoreactive neurons substantially decreased during further development. In 20-day old and older animals, we observed only few TRPV1-immunoreactive neurons in sympathetic ganglia. Finally, the percentage of neurons containing these types of neurons, become similar to adult animals to the end of the first month of life.

Morphological features of the TRPV1-immunoreactive neurons were studied in thoracic spinal nerve sensory ganglion in 10-, 20-, 30-, 60- and 90-day-old rats under normal conditions and after chemical deafferentation caused by capsaicin (100 mg/kg) subcutaneous injection at postnatal day 2. TRPV1-immunoreactive neurons differed in their morphometric characteristics: positive neurons had very small and small sizes, negative cells had the small, medium and large sizes. Capsaicin treatment of newborn rats was shown to change age dynamics of TRPV1-positive neurons resulting in the reduction of the average cell cross-sectional area and cell numbers during the whole period of observation.

Neuropeptide Y (NPY) containing 36 amino acid residues belongs to peptides widely spread in the central and peripheral nervous system. NPY and its receptors play an extremely diverse role in the nervous system, including regulation of satiety, of emotional state, of vascular tone, and of gastrointestinal secretion. In mammals, NPY has been revealed in the majority of sympathetic ganglion neurons, in a high number of neurons of parasympathetic cranial ganglia as well as of intramural ganglia of the metasympathetic nervous system. At present, six types of receptors to NPY (Y1-Y6) have been identified. All receptors to NPY belong to the family of G-bound proteins. Action of NPY on peripheral organs-targets is predominantly realized through postsynaptic receptors Y1, Y3-Y5, and presynaptic receptors of the Y2 type. NPY is present in large electron-dense vesicles and is released at high-frequency stimulation. NPY affects not only vascular tone, frequency and strength of heart contractions, motorics and secretion of the gastrointestinal tract, but also has trophic effect and produces proliferation of cells of organs-targets, specifically of vessels, myocardium, and adipose tissue. In early postnatal ontogenesis the percent of the NPY-containing neurons in ganglia of the autonomic nervous system increases. In adult organisms, this parameter decreases. This seems to be connected with the trophic NPY effect on cells-targets as well as with regulation of their functional state.

Background discharges of single neurons were studied from the superior cervical ganglion in newborn, 10-, 20-day-old, 1-, 2- and 6-month-old rats. In all age groups, the largest proportion of neurons exhibited aperiodic activity. The percentage of neurons with respiratory rhythmic was less. In newborn and 10-day-old rats, the frequency of discharges was low. Discharge frequency increased in 20-day-old rats. In 20-day-old and more adult rats, we found neurons bursting with cardiac frequency. The means of frequency did not statistically differ in 1-, 2- and 6-month-old rats. Thus, the pattern of neuronal activity is formed during the development in 20-day-old rats. Final maturation of this pattern is observed in 1-month-old rats.

The aim of this work was to study the anatomical characteristics of the stellate ganglion (SG) and the morphometric characteristics of its neurons in rats of different age groups (newborn, 10-, 20-, 30-, 60- and 180-day-old) using anatomical and histological methods. The results obtained indicated that in rats since birth there were three variants of branch origin from the medial margin of SG. No differences were observed in these variants between right and left SG. The sizes of both SG and its neurons increased during the first two months of postnatal development. The density of neurons in SG sections decreased from the moment of birth until the six months of age. The number of SG neurons did not change significantly in the postnatal ontogenesis. Thus, SG in rats is anatomically formed by the moment of birth, while the sizes and morphometric characteristics of SG neurons become finally stabilized by the second month of age.

Electrical activity of the cervical sympathetic trunk was studied in newborn, 10-, 20-, 30-day-old, two- and six-month-old rats and cats using the spectral analysis. The amplitude of discharges increased from the period of birth until the first moth of life in rats and until 20 days in cats. Frequencies synchronous with cardiac and respiration those were revealed in all animals. Heart-related frequencies were predominant in rats older than 20 days. Other frequencies were lower. In kittens, we did not observe any age-dependent changes of the spectrum of sympathetic nerve discharge. Discharges with high frequencies were observed in cats from the moment of birth.

The aim of this study was to determine the localization and morphometric characteristics of the stellate ganglion (SG) neurons containing muscarinic and purinoreceptors in rats of different ages (newborn, 10-, 20-, 30-, 60-, and 180-day-old) using the immunocytochemical methods. The results obtained indicated that in all the animals studied, the major part of neurons contained immunopositive P2X2, P2X6 purinoreceptors and M1 cholinoreceptors since birth onwards. A few of the neurons containing P2X3 purinoreceptors were detected in all the stages of postnatal development; these neurons were scarce in rats up to 10 days of life, after which their number increased to reach a maximal value in 20-day-old animals and then declined again. No significant changes were found in the proportion of neurons expressing M1 cholinoreceptors and P2X2, P2X6 purinoreceptors during the ontogenesis. Thus, the muscarinic synaptic transmission was already present in SG of rats by the time of their birth, while the final set of purinoreceptors on the neurons of sympathetic ganglion was formed by the age of 30 days.

Localization and the morphometric characteristics of NADPH-diaphorase--(NADPH-d)-positive neurons were studied in the superior cervical ganglion (SCG), stellate ganglion (SG) and the celiac ganglia (CG) in newborn, 10-, 20-, 30-, 60 and 180-day-old rats, mice and cats. No NADPH-d-positive neurons were found in rats and mice of all the age groups studied. In cats, the largest proportion of NADPH-d-positive neurons was found in the SG, the smaller one--in the SCG, while only the individual neurons we detected in the CG, irrespective of the animal age. In the SG, the proportion of NADPH-d-positive neurons increased during the first 20 days of life and then decreased after 30 days till the end of the second month. The content of NADPH-d-positive neurons in the CG and SCG d-remained unchanged during the development. There were no significant differences in the cross-sectional area between the neurons located in the different ganglia of animals from the same age group. It is concluded that the age development of NADPH-d-positive neurons in different sympathetic ganglia occured heterochronously was finished by the end of the second month of life.