Antistress effect of Semax in the course of recovery of spleen lymphoid structures after the stress in rats with different behavioral activity.

We studied the effect of antistress peptide Semax, an ACTH4-10 analogue, on the cellular composition of spleen lymphoid structures in Wistar rats with different stress tolerance in the course of post-stress recovery (days 1, 3, 14, and 30). Preliminary administration of Semax alleviates stress-induced proliferation of macrophages and destructive processes in functionally active zones of the rat spleen on days 1, 3, and 14 after the stress exposure, which attests to its capacity to reduce the adverse effects of 1-h stress load on proliferation of macrophages and destructive processes in functionally active zones of this organ.

Dizocilpine and cycloheximide prevent inhibition of c-Fos gene expression by delta sleep-inducing peptide in the paraventricular nucleus of the hypothalamus in rats with different resistance to emotional stress.

The effects of the non-competitive NMDA-receptor blocker MK-801 (dizocilpine) and the protein synthesis inhibitor cycloheximide on the delta sleep-inducing peptide (DSIP) inhibition of c-Fos immediate early gene expression were studied in the parvocellular subdivision of the hypothalamic paraventricular nucleus (pPVN) of male Wistar rats with either high or low resistance to emotional stress, predicted from differences in their open-field behaviour. The experiments show that intraperitoneal (i.p.) DSIP injection (60 nmol/kg) decreased the number of Fos-immunoreactive (Fos-IR) cells in the pPVN, activated by immobilization. The NMDA-receptor antagonist dizocilpine (MK-801) (90 nmol i.c.v.) prevented the inhibition of c-Fos expression by DSIP in the pPVN of rats predisposed to emotional stress. The protein synthesis inhibitor cycloheximide (210 nmol i.c.v.) prevented the inhibition of c-Fos expression by DSIP in the pPVN of rats that were resistant to emotional stress. The experiments indicate that the DSIP effect on c-Fos gene expression might be mediated by NMDA-receptors. DSIP may induce production of some protein transcription factors, transmitting a signal from membrane NMDA-receptors to the nucleus.

[Effect of dipeptide vilon on emotional stress resistance in rats]. / Vliianie dipeptida vilona na ustoichivost' krys k émotsional'nomu stressu.

Effects of synthetic thymomimetic vilon on open field behaviour, immediate early gene c-Fos expression in paraventricular hypothalamus properties of organs sensitive to emotional stress, and characteristics of albumin in the blood plasma in male Wistar rats, were investigated and are discussed in the article. It is shown that intraperitoneal vilon injection rises the resistance against emotional stress according to prognostic indexes open field behaviour. Vilon administration also inhibits hypertrophy of the adrenals, involution of the thymus, and elevates concentration of albumin in the blood plasma. The number of Fos-immunoreactive neurons in the paraventricular hypothalamus was lower after vilon administration especially in rats resistant against emotional stress.

[Gene c-Fos expression in brain of rats resistant and predisposed to emotional stress after intraperitoneal injection of the ACTH(4-10)analog--semax]. / Ekspressiia gena c-Fos v mozge u krys s razlichnoi ustoichivost'iu k émotsional'nomu stressu v usloviiakh vnutribpiushinnogo vvedeniia analoga AKTG(4-10)--semaksa.

The effect of the ACTH(4-10) analog Semax on immediate early gene c-Fos expression was studied in Wistar rats with high and low resistance to emotional stress under the usual conditions and during psychoemotional loading. Fos-immunoreactive cells in the were counted automatically with the help of a computer. It was shown that under the usual conditions the intraperitoneal Semax injection induced immediate early gene c-Fos expression in the lateral septal region in rats predisposed to emotional stress and in the paraventricular hypothalamus in rats of both groups. Preliminary Semax injection decreased the stress-induced c-Fos expression in the paraventricular hypothalamus and medial septum in rats predisposed to emotional stress and tended to reduce the number of stress-induced c-Fos-immunopositive cells in the lateral septum and basolateral amygdala in both groups of animals. The obtained data suggest that Semax differently affects the immediate early c-Fos gene expression in the brain of rats resistant and predisposed to emotional stress and this effect reflects the antistressor properties of the regulatory peptide.

Delta-sleep inducing peptide (DSIP) and ACTH (4-10) analogue influence fos-induction in the limbic structures of the rat brain under emotional stress.

The effects of the ACTH (4-10) analogue, ACTH (4-7)-Pro-Gly-Pro, and delta-sleep inducing peptide (DSIP) on the induction of Fos immunoreactivity in the hypothalamic parvocellular paraventricular nucleus (pPVN) and limbic brain regions were studied in Wistar rats with high (resistant) or low (predisposed) resistance to emotional stress, predicted from differences in their open-field behaviour. Fos-immunoreactive (Fos-IR) cells were counted in brain sections automatically with a computer-based image analyser. Under basal conditions, Fos-IR cell numbers were greater in the pPVN in the predisposed rats, but were lower than in the resistant rats in the basolateral amygdala and medial and lateral septum. Intraperitoneal DSIP injection (30 µg/kg) increased basal Fos-IR cell number in the pPVN and lateral septum in resistant rats, with no effects in predisposed rats. ACTH (4-10) analogue (50 µg/kg)increased Fos expression in the pPVN in both resistant and predisposed rats, with essentially no effects in the basolateral amygdala or medial and lateral septum. Emotional stress (60 min restraint and intermittent subcutaneous electrical shocks) increased Fos expression in the pPVN and medial and lateral septum similarly in predisposed and resistant rats, but in the basolateral amygdala in only the predisposed rats. Intraperitoneal DSIP injection reduced the increases in Fos-IR cell number after emotional stress, particularly in predisposed rats. In predisposed rats DSIP decreased the number of Fos-IR cells in the pPVN and the medial and lateral septum, with no change in the basolateral amygdala. In resistant rats, DSIP decreased Fos expression only in the lateral septum. ACTH (4-10) analogue injection inhibited stress-induced Fos expression in the pPVN and the medial septum, but only in predisposed rats. The experiments indicate that DSIP and ACTH (4-10) analogue reduce pPVN and limbic neurone responses to emotional stress in the rats predisposed to emotional stress; the effects on Fos expression may play a role in the biological activities of these peptides.

Expression of the c-fos gene during emotional stress in rats: the clocking effect of delta sleep-inducing peptide.

Emotional stress induced more marked increases in the expression of the c-fos gene in limbo-reticular structures of the brain in rats prognostically predisposed to emotional stress. I.p. doses of delta sleep-inducing peptide (DSIP) (60 nmol/kg) weakened the stress-induced expression of the c-fos gene. This effect was more apparent in animals predisposed to emotional stress, in which preliminary injections decreased stress-induced c-fos expression in the paraventricular hypothalamus and the medial and lateral parts of the septum. The decreased expression of the early gene c-fos in emotional stress after preliminary dosage with DSIP may reflect the leading mechanism of the anti-stress action of this peptide.

[c-fos Gene expression during emotional stress in rats: blocking by delta sleep-inducing peptide]. / Ekspressiia gena c-fos pri émotsional'nom stresse u krys: blokiruiushchaia rol' peptida, vyzyvaiushchego del'ta-son.

An emotional stress induces an obvious immediate early gene c-fos expression in the brain limbic structures in the rats predisposed to emotional stress. Administration of the delta-sleep-inducing peptide (DSIP) was shown to inhibit the c-fos expression. It led to an obvious inhibition of the c-fos expression in paraventricular nuclei of the hypothalamus, medial and lateral parts of the septum of rats predisposed to emotional stress. This mechanism seems to play an important role in the DSIP anti-stress effects.

[Low-molecular peptides in food as factors altering the resistance of rats to emotional stress]. / Nizkomolekuliarnye peptidy pishchi kak faktory izmeneniia ustoichivosti krys k émotsional'nomu stressu.

The authors studied the resistance of animals to emotional stress when they were given in the diet, as a source of protein, casein and a protein fraction composed of a mixture of amino acids and low-molecular peptides (18 and 2.7%) obtained by reprocessing Saccharomyces cerevisiae yeasts, biomass. The ECG, rheovasogram, systolic arterial pressure, and respiratory rate were studied in rats given a diet containing 18 and 2.7% low-molecular peptides (controls) and in the same animals after 24-hour immobilization. Addition of low-molecular peptides in the indicated concentration to the diet reduced the resistance of animals to emotional stress.

[Effects of beta endorphin and delta-sleep inducing peptide on resistance to emotional stress]. / Vliianie beta-éndorfina i peptida, vyzyvaiushchego del'ta-son, na ustoichivost' k émotional'nomu stressu.

Enzyme immunoassay was used to study the contents of beta-endorphin and delta-sleep inducing peptide (DSIP) in blood and hypothalamus in rats of Wistar and August lines under acute emotional stress. The stress-resistance of the animals was determined by using preliminary behavior tests. The rats were divided into two groups and predisposed to acute emotional stress. It was found that the contents of these peptides in Wistar-rats, which are more resistant to emotional stress, were higher compared with the August-rats, which are more predisposed to emotional stress. It was shown that the contents of beta-endorphin and DSIP in Wistar-rats is higher than in predisposed Wistar-rats.