Comparison of the protection against neuronal injury by hypothalamic peptides and by dexamethasone

The comparative study has been carried out on hypothalamic neurohormone (pr oline-rich polypeptides-PRP) and synthetic glucocorticoid dexamethasone (DE X) protective properties at the systemic (i/m) administration. Both backgro und and evoked electrical activity (on n.ischiadicus stimulation) of single neurons in the lumbo-sacral part (laminae II-VI and VII-VIII by Rexed) and field potentials (FP) of spinal cord were recorded during acute experiment s on intact spinal rats, subjected to Vipera Raddei (VR) venom intoxication , and chronic spinal cord trauma (hemisection). The action of PRP was chara cterized by the pronounced activation of the background activity (BA) with adaptive effect, depending on dose and initial level of BA, by results of t he statistical analysis. A high effect is received from comparatively small doses. For comparison it was used strong glucocorticoid DEX, possessing si ngle-directed but less expressed excitative action on investigated spinal c ord neurons. The initial increase of BA frequency with subsequent depressio n was the typical symptom of venom influence. A protective effect of prelim inary PRP injection is revealed on the succeeding VR venom influence. Use o f PRP and DEX causes the increase of reduced activity of neurons on the inj ury side of animals with spinal cord hemisection. It provides the possibili ty of the therapeutic utilization. It was revealed considerably more expres sed PRP action on neurodegenerative process connected to spinal cord injury (in comparison with DEX). The influence of hormones was compared in identi cal conditions of experiments on non-injured (control) and injured sides. T aking into consideration revealed protection characteristic of PRP and also the ability of snake venom to stabilize and to prolong its action combined with these preparations, the assumption is made on prospective use of the specified combination in clinical practice.