[Morphological and functional changes of nonapeptidergic cells in a surviving series of the rat hypothalamus under the effect of thyroliberin]. / Morfofunktsional'nye izmeneniia nonapeptidergicheskikh kletok v perezhivaiushchikh srezakh gipotalamusa krys pod vliianiem tiroliberina.

Direct effect of thyroliberine on nonapeptidergic cells of supraoptic and paraventricular nucleus was studied in the experiment on surviving sections of hypothalamus. The inclusion of H3 thyroliberine into vasopressinergic cells and decrease of functional activity of vasopressin and oxytocinergic cells in both hypothalamic centres which is expressed in decrease of nucleolar size of these cells was demonstrated.

[Morphofunctional characteristics of rat thyroid gland under the combined effect of oxytocin and adrenaline]. / Morfofunktsional'naia kharakteristika shchitovidnoi zhelezy u krys pri sochetannom vozdeistvii oksitotsina i adrenalina.

The influence of oxytocin, adrenalin and their combination on rat thyroid gland was studied after intraperitoneal administration of these hormones and following incubation of thyroid gland fragments in media, containing the neurohormones. Thyrostimulating effect of oxytocin (increase in thyrocyte height and 3H-leucine incorporation) was demonstrated in in vivo and in vitro experiments. Adrenaline did not cause morphofunctional changes in thyrocytes although it suppresses oxytocin thyrostimulating effect when administered simultaneously with it in both in vivo and in vitro experiments.

[The effect of thyroliberin on the nonapeptidergic hypothalamo-hypophyseal neurosecretory system in rats (in-vivo and in-vitro research)]. / Vliianie tireoliberina na nonapeptidergicheskuiu gipotalamo-gipofizarnuiu neirosekretornuiu sistemu u krys (issledovanie in vivo i in vitro).

A single i.p. injection of the thyrotropin-releasing hormone (TRH) decreased the plasma vasopressin in rats. A direct effect of the TRH involved a diminishing of the nucleoli size in oxytocin cells. The data obtained prove a direct effect of the TRH on the release and secretion processes in the nonapeptidergic cells in the paraventricular and supraoptic nuclei.

[A morphofunctional analysis of the nuclear apparatus of the nonapeptidergic neurosecretory cells in the vertebrate hypothalamus]. / Morfofunktsional'nyi analiz iadernogo apparata nonapeptidergicheskikh neirosekretornykh kletok gipotalamusa pozvonochnykh.

A vast comparative material obtained on fishes, amphibians and mammals has been analysed using ecological and experimental histophysiological approaches. The structural organization of the nuclear apparatus of nonapeptidergic neurosecretory cells, especially in the lower vertebrates has been clearly shown to differ from that of the classic neurones. Morphometrical characteristics of nonapeptidergic neurosecretory cells of hypothalamic centers can be used for a reliable evaluation of their functional conditions. A high intensity of protein metabolism in nonapeptidergic cells of magnocellular hypothalamic centers leads to a bigger nucleolus/nucleus relation for these cells in parvocellular centers. All this proves the necessity of the morpho-functional analysis of nuclear apparatus of neurosecretory cells.

[Accessory groups of nonapeptidergic cells in the diencephalon of intact and hypophysectomized rats]. / Dopolnitel'nye gruppy nonapeptidergicheskikh kletok promezhutochnogo mozga u intaktnykh i gipofizéktomirovannykh krys.

Accessory groups (AG) of oxytocin (OT)--and vasopressin (VP)--ergic cells (circular, perifornical, ventro- and dorsolateral groups and periventricularly localized nonapeptidergic cells) were studied morphometrically in intact and hypophysectomized rats. Additionally, the AG of medulla stria thalamus was demonstrated and investigated. The total number of nonapeptidergic cells in the AG is about 600 cells. The AG consist of OT-ergic cells predominantly (58%) except the perifornical group (68%) VP-ergic cells) and ventrolateral group (equal propotion). 7 days after hypophysectomy the size of perikaryon, nucleus and nucleolus of the cells in AG decreased, though, in contrast to the supraoptic and paraventricular hypothalamic centres, no degeneration of cell occured. That is why it is possible to suggest, that axons of the AG cells do not project to the posterior pituitary. The absence of hypertrophy of the AG cells in compensatory function of degenerating cells in the supraoptic and paraventricular nuclei indicates a functional diversity of these nonapeptidergic cells.

[The reaction of the nonapeptidergic neurosecretory cells of the hypothalamic accessory groups to cold and immobilization stresses in rats]. / Reaktsiia nonapeptidergicheskikh neirosekretornykh kletok dopolnitel'nykh grupp gipotalamusa na kholodovoi i immobilizatsionnyi stress u krys.

Male Wistar rats were subjected to stresses of two different kinds: cooling (2 h at 4 degrees C) or immobilization (20 min). In the rat hypothalamus, oxytocinergic (OTE) and vasopressinergic (VPE) cells were studied immunohistochemically (PAP-method) in following magnocellular accessory groups: circular (CG), perifornical (PFG), ventrolateral (VLG), dorsolateral (DLG), extrahypothalamic (EHG), and periventricularly localized OTE cells (PVC). In cooled rats, sizes of cellular nucleoli increased significantly in both OTE and VPE cells of the CG, EHG and PVC indicating activation of hormone production. The immobilization stress caused the reverse changes of morphometric characteristics in the groups. Signs of VPE cell activation were revealed after both cooling and immobilization in the PFG only. The cells of VLG and DLG did not change significantly under both stresses. It is concluded that the accessory groups of nonapeptidergic cells in the hypothalamus are functionally different and each of them is of particular significance in the organism. The role of the accessory groups for peripheral endocrine gland regulation is discussed.

[A morphofunctional study of the hypothalamic postoptic nucleus after hypophysectomy, cooling and immobilization in rats]. / Morfofunktsional'noe issledovanie postopticheskogo iadra gipotalamusa posle gipofizéktomii, okhlazhdeniia i immobilizatsii krys.

Response of the vasopressin (VP) and oxytocin (OT) cells of hypothalamic post optical nucleus (PON) was studied in male Wistar rats under various experimental conditions. Seven days after hypophysectomy, the majority of both VP- and OT-cells became pyknomorphic which seemed to be the result of transsection of the PON-cell axons and indicated that the PON-cells released neurohormones from the posterior pituitary into the blood. When rats were cooled (2 h at 4 degrees C), the size of nucleoli in VP-cells diminished significantly, but in rats stressed by severe immobilization (20 min) these cells revealed clear signs of activation. In contrast to that, no changes were observed in the OT-cells after these treatments. The functional relation of the PON and thyroid gland is discussed.

[The significance of feedback in accomplishing the rat hypothalamic nonapeptidergic center reaction to short-term immobilization stress]. / Znachenie obratnykh sviazei dlia osushcestvleniia reaktsii nonapeptidergicheskikhtsentrov gipothalamusa krys na kratkovremennyi immobilizatsionnyi stress.

Stress response of oxytocin- and vasopressinergic cells in the supraoptic and paraventricular centers of the hypothalamus was studied morphometrically in rats with intact hypophysis and 7 days after hypophysectomy. Severe immobilization (for 20 min.) was applied as an unspecific short-term stress. In nonoperated rats the immobilization resulted in diminution of functional activity of vasopressinergic cells in the paraventricular nucleus exclusively: nucleolar volume of these cells reduced to 80% (P < 0.05). The same pattern of reaction of nonapeptidergic cells was revealed in the hypophysectomized rats under stress immobilization. The stress blood concentration of vasopressin, ACTH, 11-HOCS clearly increased in nonoperated rats but not in the hypophysectomized rats. TSH plasma concentration and the thyroid gland activity did not alter under stress in both groups of rats. Thus, the data evidence for the response of nonapeptidergic hypothalamic centers is not influenced by fluctuations of the hormone level in blood under short-term stress.

[The blocking effect of adrenaline on the thyroid-stimulating effect of vasopressin in rats]. / Blokiruiushchee vliianie adrenalina na tirostimuliruiushchii éffekt vasopressina u krys.

Effect of various doses of oxytocin, vasopressin or adrenalin on the thyroid gland activity was studied in hypophysectomized and nonoperated rats 20 minutes after a single injection of the neurohormones. The minimal applied dose of the neurohormones stimulated increasing of their concentration in blood up to level typical for stress reaction. Injection of oxytocin led to no effect at any dose. In nonoperated rats vasopressin stimulated the thyroid gland but did not influence on TSH level in blood. In hypophysectomized rats thyrostimulating effect of vasopressin was also detected need. Adrenalin injection inhibited the thyroid gland function in both nonoperated and hypophysectomized rats. Effect of adrenalin in combination with vasopressin was like the action of adrenalin alone. Thus, it is possible to assume that under stress conditions a high blood level of adrenalin attenuates thyrostimulating effect of vasopressin.

[Effect of arginine-vasopressin on the rat thyroid gland in vitro]. / Effekt arginin-vazopressina na shchitovidnuiu zhelezu krysy in vitro.

The response of the rat thyroid gland to arginine-vasopressin in vitro was studied to clear a possibility of a direct regulation of this gland by hypothalamic nonapeptide neurohormones. The function of the thyroid gland was estimated by thyrocyte height and quantity of the autoradiographs on a thyrocyte. AVP makes more active hormone synthesis in thyrocytes after 30 min of incubation and it stimulates both synthesis and secretion of the thyroid hormones in 2 hours of incubation. The higher concentrations of AVP activate the thyroid hormone synthesis but not the secretion.

[Thyroid stimulating effect of exogenous vasopressin and oxytocin in hypophysectomized rats during immobilization stress]. / Tirostimuliruiushchii éffekt ékzogennogo vazopressina i oksitotsina u gipofizéktomirovannykh krys pri immobilizatsionnom stresse.

Male Wistar rats were hypophysectomized 1 week before restraint stress. The hypophysectomy caused a decrease of blood vasopressin (30%, P less than 0.05) and a diminution of the thyroid activity (the thyrocyte height lowered to 43%, P less than 0.01). The TSH concentration was about normal and remained constant during the experiment. After 20 min of the restraint stress, the vasopressin concentration reached 178% (P less than 0.01), but the thyroid did not response in rats with the intact hypophysis. In the hypophysectomized rats, the restraint stress caused neither essential changes of the blood vasopressin nor the thyroid function as compared with the hypophysectomized control. An injection of vasopressin (5.0 ng/100 g) or oxytocin (15.0 ng/100 g) resulted in a slight activation of the thyroid in the hypophysectomized rats but significantly stimulated in when combined with the restraint stress; vasopressin injection led to an increase of the thyrocyte height to 152% (P less than 0.01), oxytocin--to 126% (P less than 0.05). Thus, in hypophysectomized rats, vasopressin and oxytocin can influence the thyroid directly. Stressful conditions facilitate the thyroid stimulating effect of these nonapeptide neurohormones.