Uterus sympathetic nervous apparatus in sexual cycle dynamics in rats

Uterus sympathetic nervous apparatus in various phases of sexual cycle in rats was studied with the microspectral fluorescent method. The main part of nervous fibers in the form of perivascular plexus and terminals deviating from them are localized in myometrium. We suppose presence of reserve ("silent") nervous fibers in uterus which explains the inconstancy of their revealing in the organ. Catecholamines and serotonin are identified in varicose enlargements and intervaricose parts of nervous fibers by the way of microspectrofluorometry. Their concentration in probing places is characterized by high degree of linear correlation at all stages of sexual cycle. Maximal concentration of bioamines in most structural elements of uterus sympathetic nervous apparatus in detected in late diestrus. Stages of early and late estrus and proestrus are characterized by low levels of monoamines in adrenergic fibers. A number of reliable differences between bioamines saturation and spatial distribution density of nervous fibers in the neck and body of the womb are revealed.     

Characteristics of the compensatory repair processes in the thyroid of 1-month-old rats as affected by sympathectomy

A considerable decrease in the amount of sympathetic nervous cells in neonatal rats injected guanethidine resulted in the depression of thyroid gland functional activity in 1-month-old animals, there was an apparent parallel increase in the proliferative activity of the gland. A 2/3 thyroidectomy led to the functional tension of the remaining part of the organ. A comparison of compensatory-reparative processes after thyroidectomy has shown similarity of reparative changes in experimental and control rats, however, the degree of repair potential was much higher in the sympathectomized thyroid gland.     

SCN efferents to peripheral tissues: implications for biological rhythms.

The suprachiasmatic nucleus (SCN) is the principal generator of circadian rhythms and is part of an entrainment system that synchronizes the animal with its environment. Here, we review the possible communication of timing information from the SCN to peripheral tissues involved in regulating fundamental physiological functions as revealed using a viral, transneuronal tract tracer, the pseudorabies virus (PRV). The sympathetic nervous system innervation of the pineal gland and the sympathetic outflow from brain to white adipose tissue were the first demonstrations of SCN-peripheral tissue connections. The inclusion of the SCN as part of these and other circuits was the result of lengthened postviral injection times compared with those used previously. Subsequently, the SCN has been found to be part of the sympathetic outflow from the brain to brown adipose tissue, thyroid gland, kidney, bladder, spleen, adrenal medulla, and perhaps the adrenal cortex. The SCN also is involved in the parasympathetic nervous system innervation of the thyroid, liver, pancreas, and submandibular gland. Individual SCN neurons appear connected to more than one autonomic circuit involving both sympathetic and parasympathetic innervation of a single tissue, or sympathetic innervation of two different peripheral tissues. Collectively, the results of these PRV studies require an expansion of the traditional roles of the SCN to include the autonomic innervation of peripheral tissues and perhaps the modulation of neuroendocrine systems traditionally thought to be controlled solely by hypothalamic stimulating/inhibiting factors.     

Age-related changes in the innervation of the prostate gland

The adult prostate gland grows and develops under hormonal control while its physiological functions are controlled by the autonomic nervous system. The prostate gland receives sympathetic input via the hypogastric nerve and parasympathetic input via the pelvic nerve. In addition, the hypogastric and pelvic nerves also provide sensory inputs to the gland. This review provides a summary of the innervation of the adult prostate gland and describes the changes which occur with age and disease. Growth and development of the prostate gland is age dependent as is the occurrence of both benign prostate disease and prostate cancer. In parallel, the activity and influence of both the sympathetic and parasympathetic nervous system changes with age. The influence of the sympathetic nervous system on benign prostatic hyperplasia is well documented and this review considers the possibility of a link between changes in autonomic innervation and prostate cancer progression.     

The innervation of the thyroid gland of the sand rat (Psammomys obesus)

It has been reported on the occurence of vegetative neurons in the stroma of the sand rat (Psammomys obesus) thyroid gland. The cells show all the typical signs of autonomic nerve cells. In contrast to neurons appearing in the pancreas of the sand rat, the neurons in the thyroid gland occur in most cases as singular neurons. The importance of the sympathetic innervation for the thyroid function has been discussed and the close relationship between thyroid hormone secretion and biogenic amines localized in the thyroid mast cells has been described as well.     

Function of the serotoninergic system of the thyrotoxic thyroid

The state of serotoninergic system in thyrotoxic and euthyroid gland were compared. It was shown that in patients with hyperthyroidism (diffuse toxic goiter) serotonin and 5-hydroxytryptophan content, velocity and the latter uptake were augmented. The authors stress the role of the delay in serotonin oxidative deamination as one of the reasons for increased serotonin content in thyrotoxic thyroid gland. Possible ways of increasing intrathyroid serotonin accumulation and its role in the development of thyroid hyperfunction are discussed.     

Ipsilateral thyroid growth and depressed thyroid hormone synthesis and content after unilateral superior cervical ganglionectomy in rats

The role of the sympathetic nervous system in the control of the goitrogenic response was examined in adult male rats subjected to unilateral superior cervical ganglionectomy 12-30 days earlier. A spontaneous goiter as well as an increased thyroid growth after the administration of the goitrogenic agents methylmercaptoimidazole and thyrotropic stimulating hormone (TSH) were found in the ipsilateral lobe. Norepinephrine and epinephrine content decreased significantly by 80 and 31%, and thyroxine (T4) and triiodothyronine (T3) content by 24 and 15%, in the ipsilateral lobe. After the injection of a tracer dose of 125I, percent radioactivity incorporation to diiodotyrosine (DIT) was higher, and that to monoiodotyrosine (MIT) lower, in the ipsilateral lobe; additionally a lower ratio "labeled T3 + T4/labeled DIT" was found in the denervated thyroid lobe. These results suggest that the sympathetic nerve terminals in the thyroid gland modulate the organ's response to circulating TSH.     

Cholinergic nerves in the thyroid gland

Summary The cholinergic innervation of the thyroid gland has been studied in the human. AChE positive nerve fibers are localized in the wall of the thyroid artery, arranged in two plexuses, a superficial (adventitial) and a deep one (medial). The glandular tissue is provided with cholinergic nerve fibers, localized between and around thyroid follicles. The present results suggest that the endocrine activity of the thyroid gland is also under the control of the autonomic nervous system.     

Stimulation-depletion of serotonin and noradrenaline from vesicles of sympathetic nerves in the pineal gland of the rat

Summary The pineal gland of the rat receives a rich nervous supply originating from the superior cervical ganglia. These fibers contain serotonin in addition to their neurotransmitter, noradrenaline. Cytochemical studies at the ultrastructural level have shown that both amines are present in the cores of the granular vesicles that are characteristic of these nerves. It is presently shown that the bilateral electrical stimulation of the preganglionic fibers innervating the ganglia markedly reduces the number of small sites reacting cytochemically for both noradrenaline and serotonin, these sites corresponding to the cores of small granular vesicles, while the larger reactive sites (cores of large vesicles) remain unaltered. The vesicles are retained in nerve terminals after stimulation, as observed in conventionally processed tissues, although with altered sizes and shapes. Apart from these cytochemical and structural changes, nerve stimulation also reduces the endogenous noradrenaline content of the pineal gland. Thus, both noradrenaline and serotonin are released from their storage sites in pineal sympathetic nerves after electrical stimulation in vivo. This suggests the possibility that several substances with presumed transmitter or modulatory functions might be simultaneously released by nerve impulses from a given nerve terminal.     

Dynamics of postnatal histogenesis of the thyroid in normal rats and after sympathectomy

The changes of the thyroid gland and neurocytes of the cranial sympathetic ganglia were followed in rats of different ages after guanethidine injections with the use of radioimmunological assay, electron microscopy and morphometry. The injection of 15 mg of the drug per kg of body weight within the first two weeks after birth caused the death of over 80% of the cells in the sympathetic ganglion. In the sympathectomized 15-day- and 1-month-old rats the functional activity of the thyroid gland was markedly reduced. Later on, intrathyroid hormonogenesis somewhat increases due, apparently, to partial recovery of the organ adrenergic innervation and increase in the production of thyrotropic hypophysial hormone and calcitonin.     

Sympathetic thyroidal vasoconstriction is not blocked by a neuropeptide Y antagonist or antiserum

Sympathetic nerve fibers to thyroid blood vessels contain both norepinephrine (NE) and neuropeptide Y (NPY). To assess the involvement of endogenous NPY in the sympathetic neural control of thyroid blood flow, appropriate doses of a selective NPY antagonist, -trinositol, and an NPY antiserum (NPY-AS) were used during cervical sympathetic trunk stimulation in anesthetized rats. During all experiments, thyroid blood flow was continuously monitored by laser Doppler blood flowmetry. Neither -trinositol nor NPY-AS blocked the thyroidal vasoconstriction evoked by either the first or second stimulation of the cervical sympathetic trunks. Our results suggest that NPY is not involved either directly or indirectly during acute sympathetic vasoconstriction in the rat thyroid gland.     

Annual variations of the NPYergic innervation of the pineal gland in the European hamster (Cricetus cricetus): a quantitative immunohistochemical study

A prominent innervation of the pineal gland of the European hamster with nerve fibres containing neuropeptide Y (NPY) and tyrosine hydroxylase (TH) was demonstrated by means of immunohistochemistry. Nearly all the TH- and NPY-immunoreactive nerve fibres in the superficial pineal gland disappeared after bilateral superior cervical ganglionectomy, showing that the majority of NPY- and TH-immunoreactive nerve fibres belonged to the sympathetic nervous system. Since, in the European hamster, preliminary studies of the NPY-fibre density in the pineal gland had indicated seasonal changes, the density of NPY-immunoreactive nerve fibre profiles was ascertained in the superficial pineal gland in a series of animals between the first part of November and late April. The highest density of NPY-immunoreactive nerve fibre profiles was observed during midwinter. On the other hand, during the same period of the year, the number of sympathetic TH-immunoreactive sympathetic nerve fibre profiles did not exhibit seasonal variation, nor did substitution of testosterone, during the sexually inactive period, affect the density of NPY-containing nerve fibres in the gland. Our results show the presence of a testosterone-independent annual variation in the content of NPY in the sympathetic nerve fibres innervating the pineal gland of the European hamster. This variation can be correlated with the changes in the daily pattern of melatonin production observed by others in the same species at this period of the year.     

Presence of chromogranin A, B and C in bovine endocrine and nervous tissues: a comparative immunohistochemical study

Summary Antisera against chromogranin A, B and C were used to study the distribution of these acidic proteins in bovine endocrine and nervous tissues. The three chromogranins occur together in several endocrine organs (adrenal medulla, anterior pituitary, endocrine pancreas) and in sympathetic ganglion cells. In the posterior pituitary, only chromogranin C and in the intermediate lobe only A and C are found. The parathyroid gland contains only A, and enterochromaffin cells are immunoreactive for A and B. Cells of the thyroid gland and some cells of the anterior pituitary apparently do not contain any chromogranins. It is concluded that the three chromogranins are not always stored together and that they are not present in all endocrine cells. This distinct localization of the chromogranins indicates some special, although still undiscovered, function for these proteins.     

Circadian rhythm of the thyroid mast cells in untreated and methylthiouracil-treated rats

Recent investigation have shown that mast cells of the rat thyroid participate in the regulation of thyroid function. Serotonin released from the mast cells influenced by thyrotropin promotes iodothyronine secretion by its effect on the thyroid follicle cells. The present histophysiological studies on the circadian rhythm in the normal rat thyroid reveal a close correlation between the number of the thyroid mast cells and the thyroid function. It has been shown that in the morning, when thyroid function is decreased, the number of the mast cells is low, but at noon it shows an increase an then is highest in the evening, when the thyroid activity is most intense. This phenomenon suggests a relationship between the mast cell function and the thyroid feedback mechanism. In methylthiouracil-treated rats inhibition of the thyroid iodothyronine production and change of the feedback mechanism function induce development of a hypertrophic goitre in which degranulation of the mast cells accompanied by release of their bioamines induce dilatation of blood vessels and increase in the thyroid blood flow. Simultaneously the circadian rhythm of the thyroid mast cell occurrence is changed, i.e. their number found in the morning gradually decreases by the evening.     

On the role of serotonin and 5-methoxy-tryptamine in the regulation of cell division in sea urchin eggs

The presence of serotonin in sea urchin eggs has been ascertained by high-performance liquid chromatography and thin-layer chromatography analysis of tissue-free bioamines. The results show the presence of both serotonin and 5-methoxytryptamine. The role of these substances in the cell division process has been studied by using the serotonin antagonists, gramine and metergoline. Both antagonists cause a significant delay of the cell division which, however, can be prevented by the addition of either 5-hydroxytryptophane, serotonin, or 5-methoxytryptamine. The effect of gramine on the different stages of the cell division process has also been investigated. Neither S phase nor mitosis are affected by the serotonin antagonist, while cleavage is delayed. The effect of serotonin seems mediated by calcium ions and cAMP. Gramine causes a marked increase in radio-calcium efflux from the fertilized egg, and at the same time lowers the cAMP level.     

Lack of Tryptophan Hydroxylase-1 in Mice Results in Gait Abnormalities

The role of peripheral serotonin in nervous system development is poorly understood. Tryptophan hydroxylase-1 (TPH1) is expressed by non-neuronal cells including enterochromaffin cells of the gut, mast cells and the pineal gland and is the rate-limiting enzyme involved in the biosynthesis of peripheral serotonin. Serotonin released into circulation is taken up by platelets via the serotonin transporter and stored in dense granules. It has been previously reported that mouse embryos removed from Tph1-deficient mothers present abnormal nervous system morphology. The goal of this study was to assess whether Tph1-deficiency results in behavioral abnormalities. We did not find any differences between Tph1-deficient and wild-type mice in general motor behavior as tested by rotarod, grip-strength test, open field and beam walk. However, here we report that Tph1 (−/−) mice display altered gait dynamics and deficits in rearing behavior compared to wild-type (WT) suggesting that tryptophan hydroxylase-1 expression has an impact on the nervous system.     

Sympathetic nervous system activity in rat thyroid: potential role in goitrogenesis

The role of sympathetic innervation in regulation of thyroid function is incompletely understood. We, therefore, carried out studies in rats utilizing techniques of norepinephrine turnover to assess thyroid sympathetic activity in vivo. Thyroidal sympathetic activity was increased 95% by exposure to cold (4 degrees C), 42% by chronic ingestion of an iodine-deficient diet, and 32% in rats fed a goitrogenic diet (low-iodine diet supplemented with propylthiouracil). In addition, fasting for 2 days reduced sympathetic nervous system activity in thyroid by 38%. Thyroid growth and 125I uptake were also compared in intact and decentralized hemithyroids obtained from animals subjected to unilateral superior cervical ganglion decentralization. Unilateral superior cervical ganglion decentralization led to a reduction in thyroid weight, in 125I uptake by thyroid tissue, and in TSH-induced stimulation of 125I uptake in decentralized hemithyroids. These results suggest that sympathetic activity in thyroid contributes to gland enlargement and may modulate tissue responsiveness to TSH.     

Neuromedin U-like immunoreactivity in the thyroid gland of the rat

Summary Neuromedin U is a novel neuropeptide found to have a widespread distribution extending throughout the mammalian central nervous system, gastrointestinal tract and the endocrine cells of the pituitary gland. In order to investigate the possibility that neuromedin U-like immunoreactivity is also present in the thyroid gland of the adult rat we have examined its localisation and molecular nature by radioimmunoassay, immunocytochemistry and chromatographic analysis. The neuromedin U content of the whole thyroid gland was found to be 331±67 fmol/gland (mean±SEM), and this value significantly decreased (163±17 fmol/gland) as a result of 14 days of treatment with the anti-thyroid agent methimazole (10 mg/rat/day. Thyrotoxicosis induced by exogenous T4 (10 g/rat/day) failed to alter the thyroid content of this peptide. Immunostaining studies localised neuromedin U to a minor population of parafollicular C-cells in untreated animals. Complementary chromatographic studies revealed a single molecular form of neuromedin U-like immunoreactivity in thyroid tissue extracts which was indistinguishable from synthetic rat neuromedin U standard.     

The expression of neuropeptide Y immunoreactivity in the avian sympathoadrenal system conforms with two models of coexpression development for neurons and chromaffin cells.

We have studied the expression and development of neuropeptide Y-like immunoreactivity (NPY-LI) in the sympathoadrenal system of the chicken using single and double immunocytochemical techniques and radioimmunoassay. NPY-LI is expressed by neurons of the paravertebral sympathetic ganglia and by chromaffin cells of the adrenal gland in embryonic and adult chickens. The peptide is coexpressed with catecholaminergic properties in neurons. In chromaffin cells, it is also expressed with immunoreactivity to somatostatin and serotonin. We have used the expression of NPY-LI to analyze how cells that coexpress two or more neuroactive substances arrive at their final phenotype. Our results suggest that the ontogeny of coexpression in neurons of the avian paravertebral sympathetic ganglia occurs in a sequential pattern, where the expression of the peptide follows the initial expression of the "classical neurotransmitter". In contrast, in chromaffin cells, expression of the peptides occurs concomitantly with expression of catecholaminergic properties or soon after. Initially, coexpression of several neuroactive substances occurs, but this is followed by further specialization where the expression of one peptide prevails over the other. We believe that the two models of coexpression shown by our results can be used to describe the ontogeny of coexpression in other cells of the nervous system.