[The effect of tefestrol on the secretion of luteinizing hormone from the hypophysis].

The effect of tefestrol on the content of luteinising hormone in blood and hypophysis in female and male rats was studied on the basis of the radioimmunological assays. It was shown that administration of tefestrol to the female rats depending on the preparation dose and the time of administration during the estrous cycle can produce an increase and a decrease of luteinising hormone content in the material under study. In the male rats tefestrol induced a stable elevation of blood gonadotropine level.

[Modulating effect of estradiol on the sensitivity of the preoptic area neurons to noradrenaline].

Sensitivity of the preoptic area neurons to norepinephrine before and after application of estradiol was investigated. The obtained results show that estradiol influences neuron sensitivity. Microiontophoretic application of norepinephrine followed the estradiol into the preoptic area and increased the activity of single neurons in the majority of experiments.

[Treatment of patients with disorders of the ovulatory function of central etiology with preparations affecting adrenergic mechanisms].

A treatment protocol has been proposed for patients with luteal phase inadequacy of central origin employing isodrin stimulation of beta-adrenergic receptors on days 5 to 10 of the cycle and fetanol stimulation of alpha-adrenergic receptors on days 10 to 14. This protocol is recommended for use in ovarian function normalization, both alone and in combination with hormonal therapy.

[Estrogen-sensitive neurons of the preoptic area of the hypothalamus].

Microiontophoretic application of estradiol to the preoptic area of the hypothalamus enhanced the unit activity, the response being more obvious at the diestrus-2 stage and owing to the level of endogenous estrogens.

[Changes in the gonadotropic function of the rat hypophysis during development of experimental alcoholism].

Luteinizing hormone (LH) and prolactin blood plasma levels and LH level in the pituitary of alcoholic male rats were studied Alcoholic rats (heavy drinkers) have revealed hyperprolactinemia and inadequate LH secretions. The possible role of gonadotropins in the development of hypogonadism in alcoholic rats is discussed.

[Role of various types of serotonin reception in the hypothalamic modulation of the release of luteinizing hormone].

Ciproheptadin was found to depress the activating effect of serotonin in the preoptic brain area and in the hypothalamic arquate nuclei. Blockade of the type II serotonin receptors increased the content of luteinizing hormone in the blood in dioestrus-2 stage and in the morning during pro-estrus. Microiontophoretic administration of serotonin into the thalamic arquate nuclei during the blockade decreased the luteinizing hormone level in the blood in dioestrus-2 stage and in the morning during pro-estrus.

[Reaction of neurons in the arcuate hypothalamic area to the microiontophoretic application of serotonin at different stages of the estrous cycle in rats].

Among the neurons of the hypothalamic arcuate area, the center of tonic regulation of gonadotropic function, prevailed those with activating response to serotonin at the dioestrus-2 stage of the oestrus cycle, particularly in the morning hours. During prooestrus, an increased number of neurons with inhibitory responses was found, especially during evening hours. Serotonin induced a decrease in the amount of luteinizing hormone in the blood which was usually combined with an activating action of the indolamine on the neuronal activity.

[Neurotropic effect of hypophyseal somatotropin and its fragment].

The effect of sei whale somatotropin and its biologically active fragment 77-107 (under conditions of microionophoresis) on the cortical, caudate nucleus and amygdala single neuron electrical activity of the rat brain as well as on the neuron sensitivity to noradrenaline was studied. The neurons, responded to somatotropin and its fragment inhibitory action, were revealed in all the brain regions examined. The majority of neurons did not react to noradrenaline, part of them responded to noradrenaline, decreasing the impulse activity and a very small part--increased the impulse effect.

[Gonadotropic activity of the hypophysis of rats with continuous estrus induced by autotransplantation of the ovaries into the medium with low temperature].

Gonadotropic activity of the adult rat hypophyses with continuous estrus (CE), induced by ovarian autotransplantation into the concha auriculae was studied. The "summary" gonadotropin content in the hypophyses of CE rats, determined on experimental infantile young rats, was higher than in intact estrous animals. LH level, examined by radioimmunoassay, was also higher than in intact estrous rats.

[New data on the participation of beta-endorphin in the neuroendocrine control of luteinizing hormone release].

In the experiments on rats the influence of the endogenic opioid beta-endorphine on the blood and hypophysis luteinizing hormone levels was studied after microiontophoretic injection of the hormone into diencephalon preoptic region. beta-Endorphine was shown to induce a significant decrease in blood hormone level and its increase in the hypophysis. No correlation was found between the changed hormone levels in the blood and hypophysis and beta-endorphine action.

[Sensitivity of hypothalamic neurons to beta-endomorphin, met-enkephalin, and thyroliberin].

A study was made of susceptibility of hypothalamic neurons to beta-endorphine, thyroliberin and met-enkephalin applied microiontophoretically. The opioids were shown to exert a primarily unidirectional effect on the same neurons irrespective of the fact that the inhibitory action of beta-endorphine was more pronounced. The nalorphine-competitive antagonist of the opiates removed the met-enkephalin-induced inhibition.

[Sensitivity of neurons in different regions of the brain to met-enkephalin, beta-endorphin, and thyroliberin in the rat].

The oligopeptides were microiontophoretically applied to neurons of the sensory cortex, hippocampus, thalamus and septum. Metenkephalin and beta-endorphin increased activity of some neurons while decreasing it in other cells. Nalorphine antagonized the inhibition effect of metenkephalin in all the brain areas under study.

[Role of noradrenaline-sensitive neurons of the preoptic area in regulating luteinizing hormone release].

The effect of the microiontophoretic application of noradrenaline to the preoptic area of the hypothalamus on the unit activity and on the plasma and hypophysis LH levels was studied at various stages of estrous cycle. The activatory reaction of the preoptic neurons seems to increase the LH level in the blood. No direct correlation existed between the mode of the unit response to noradrenaline and the LH level changes in hypophysis.

[Comparative analysis of single central nervous system neuron sensitivity to thyrotropin-releasing hormone and its structural analog].

Sensitivity of the cortex single neurons, hippocamp, thalamus medial nucleus, periventricular and arcuate hypothalamus nuclei to the thyrotropin-releasing hormone (TRH) and its structural analog (Pyr-Ser-Leu-NH2) under conditions of their microionophoretic application by means of multichannel microelectrodes was studied and compared in experiments on rats. There was no significant similarity between TRH and its analog effects in all the test brain regions with the exception of the cortex. A significant positive correlation between their influence on the single neuron activity was recorded.

[Effect of beta-endorphin on preoptic region neuronal activity as the center of gonadotropic function regulation].

A study was made of the effect of microiontophoretic application of beta-endorphine on the activity of single preoptic neurons of the diencephalon as the regulating center of gonadotrophic function of the hypophysis. In 44.1% of cases, beta-endorphine exerted an inhibitory effect on the activity of single neurons, the depth of this effect amounted on the average to 54.

[Role of estrogen-sensitive neurons in the arcuate region of the hypothalamus in the mechanism of luteinizing hormone release].

Experiments were conducted on rats; estradiol brought to the arcuate region of the hypothalamus by means of microionophoresis led to the increase of the region of the hypothalamus by means of microionophoresis led to the increase of the blood luteinizing hormone (LH) level during the following stages of the estral cycle-diestrus 1, diestrus 2, and the first half day of the proestrus; as to the second half of the proestrus day--estradiol decreased its level. Changes in the LH level in the hypophysis under the influence of the microionophoretic introduction of estradiol into the arcuate region occurred during the second half of the day of diestrus 2 (reduction), and during the estrus (elevation). In the majority of cases a rise of the blood level was combined with the neuron activation in the arcuate region under the influence of estradiol.

Unit activity in the hypothalamic arcuate area in rats at different stages of the estrous cycle.

Changes in sensitivity to dopamine in various stages of the estrous cycle were studied in rats by microiontophoretic application to single neurons of the hypothalamic region and recording unit activity. Most arcuate neurons during the first half of the day in proestrus were shown to respond to dopamine by activation, to correspond to the raised plasma estrogen level in this phase of the estrous cycle. During the second half of the day in proestrus, when the estrogen level is minimal, and in stage diestrus-2, of all the neurons recorded the great majority responded to dopamine by inhibition.

[Dopamine sensitive neurons of the arcuate region of the hypothalamus and their role in regulating the gonadotropic function of the pituitary].

The effect of the microiontophoretic application of dopamine (DA) into the arcuate region of the hypothalamus on the sensitivity of single neurons and on the plasma and hypophysis LH levels was examined at various stages of the estrous cycle. During the estrous cycle in rats there was no significant differences in the relative number of neurons showing activation and inhibition or non-responsive to DA. However, in the first half of proestrus (P) a significant increase in the number of neurons with the excitative reaction to the iontophoretic application of DA was observed.

[The effect of thyroid hormones on inhibition of monosynaptic extensor reflexes].

In thyreotoxic cats with intact or transected spinal cord, intensity of direct and presynaptic inhibition induced by a single volley in a flexor nerve afferent fibers was diminished and the delayed postsynaptic (polysynaptic) inhibition from the skin afferent fibers was more intense than in control cats. The mechanisms for the thyroid hormone effect on the cerebrospinal control of the extensor reflex inhibition, are discussed.