Heptapeptide semax attenuates the effects of chronic unpredictable stress in rats

Antistress Action of Melanocortin Derivatives Associated with Correction of Gene Expression Patterns in the Hippocampus of Male Rats Following Acute Stress

Natural melanocortins (MCs) have been used in the successful development of drugs with neuroprotective properties. Here, we studied the behavioral effects and molecular genetic mechanisms of two synthetic MC derivatives-ACTH(4-7)PGP (Semax) and ACTH(6-9)PGP under normal and acute restraint stress (ARS) conditions. Administration of Semax or ACTH(6-9)PGP (100 μg/kg) to rats 30 min before ARS attenuated ARS-induced behavioral alterations. Using high-throughput RNA sequencing (RNA-Seq), we identified 1359 differentially expressed genes (DEGs) in the hippocampus of vehicle-treated rats subjected to ARS, using a cutoff of >1.5 fold change and adjusted p-value (Padj) < 0.05, in samples collected 4.5 h after the ARS. Semax administration produced > 1500 DEGs, whereas ACTH(6-9)PGP administration led to <400 DEGs at 4.5 h after ARS. Nevertheless, ~250 overlapping DEGs were identified, and expression of these DEGs was changed unidirectionally by both peptides under ARS conditions. Modulation of the expression of genes associated with biogenesis, translation of RNA, DNA replication, and immune and nervous system function was produced by both peptides. Furthermore, both peptides upregulated the expression levels of many genes that displayed decreased expression after ARS, and vice versa, the MC peptides downregulated the expression levels of genes that were upregulated by ARS. Consequently, the antistress action of MC peptides may be associated with a correction of gene expression patterns that are disrupted during ARS.

An integrated approach to study the molecular aspects of regulatory peptides biological mechanism

An integrated methodological approach to study the molecular aspects of short regulatory neuropeptides biological mechanism is proposed. The complex research is based on radioligand-receptor method of analysis and covers such points of peptides molecular activity as: specific binding of peptides to brain cells plasmatic membranes, formation of tissue specific synacton, influence of peptides (as allosteric modulators) on functionality of different neuroreceptors as well as delayed in time effects of peptides on receptor-binding activity of well-known neuroreceptor systems. Radiolabeled ligands in such complex study are the one of the best and precision instruments to uncover the molecular mechanism of multiple and multitarget biological effects of regulatory peptides. In this issue we used heptapeptide Semax as a model regulatory peptide, [³ H]Ach and [³ H]GABA as an effector molecules, and the rat model of stress-induced memory and behavior impairment as a morbid state. We showed the ability of Semax to modulate in a dose-dependent manner [³ H]Ach and [³ H]GABA specific binding to some of its corresponding receptors as well as to affect the number of [³ H]GABA specific binding places on rat neurons plasmatic membranes after complex stress exposure.

Influence of ACTG4-7-PGP (Semax) on Morphofunctional State of Hepatocytes in Chronic Emotional and Painful Stress

We studied the effect of intraperitoneal administration of peptide ACTG_4-7-PGP to male Wistar rats in doses of 5, 50, 150, and 450 μg/kg on the morphofunctional state of hepatocytes in chronic emotional and painful stress. A dose-dependent stress-limiting effect of the peptide was observed: it normalized the protein synthesis function of the liver and serum activity of ALT. The anticytolytic effect of the peptide increased with increasing its dose against the background of the increase in the relative number of multinucleated and multinucleolated cells and deceleration of the recovery of serum protein concentration. The decrease of hepatocyte cytolysis against the background of more intense morphological signs of protein synthesis processes attests to activation of reparative processes in the liver parenchyma via enhanced constitutional synthesis of protein.