Morphofunctional Modifications of Cells of the Preoptic Hypothalamic Nucleus of Prepubescent Rats under Conditions of Stimulation and Blocking of the α-Adrenergic and Kisspeptinergic Systems

Abstract

In experiments on prepubescent (one-month-old) male albino rats, we studied the effects of pharmacological blockade and activation of kisspeptinergic and α-adrenergic systems on neurocytes and astrocytes of the preoptic hypothalamic nucleus. Intracerebroventricular injection of kisspeptin induced activation of the processes of synthesis of proteins in neurons and astrocytes of this nucleus, which was manifested in significantly greater mean values of cross-section areas of the nuclei of these cell units. Injections of a blocker of kisspeptin receptors, Р-234, inhibited synthetic activity in neurons but not in astrocytes. Mezaton intensely activated the above-mentioned activity in cells of both types; such activation could not be eliminated completely by simultaneous injection of the kisspeptin antagonist Р-234. Prazosin suppressed synthetic processes in neurons but not in astrocytes. In the case of combined introduction of prazosin and kisspeptin, the effect of inhibition of protein synthesis in neurons was significantly weakened but could not be eliminated completely; in astrocytes, the functional activity increased. We discuss the mechanisms of action of the α-adrenergic and kisspeptinergic systems on production of gonadotropin-releasing hormone (gonadoliberin) by cells of the preoptic hypothalamic nucleus and the actions of these events on the functioning of the reproductive system.