Cholinoreceptors of early (preneural) sea urchin embryos.

Agonists of nicotinic cholinoreceptors (n-AChR) and 1-acetyl-4-methylpiperazine (100 microM) had no effect on early embryogenesis in sea urchins, while in the presence of phorbol-12-myristate-13-acetate (PMA) and various other protein kinase C activators, these agents induced rapid lysis of oocytes or early embryos, as a result of calcium shock. Many n-AChR ligands which do not penetrate into the cytoplasm (not being antagonists of muscarinic cholinoreceptors) protected against this cytotoxic effect. In the presence of PMA, acetylcholine and carbachol had actions which were much weaker than those of nicotine, while muscarine was completely inactive in these conditions.

[Effects of delta sleep-inducing peptide on the intercentral integration during experimental epilepsy].

In free behavior experiments on cats it has been shown, that the intraperitoneal injection of delta-sleep-inducing peptide (100 mg/kg) may change organization of the pathology integration-epileptic discharges did not spread all the structures simultaneously. The slow-waves were registered in central medium of the thalamus and nucl. caudati.

Conditioned motor reactions in free-moving elasmobranchs and bony fishes.

Food-getting conditioned motor reflexes to light and darkness discrimination were developed in elasmobranchs (the sharks Scyllium canicula and Galleus canis) and bony fishes (Mugil capitocum). Several distinctions in ecological and conditioned motor behavior were observed in sharks with low and high degrees of organization. There were significant differences between elasmobranchs and bony fishes in ecological and food-getting behavior and in conditioned reflex reactions.