[Pharmacologic study of the inhibition of the glomerular input to the olfactory tubercle of the frog induced by a puff of air on the olfactory mucosa].

The effects of 4-aminopyridine (10(-2) mol/l), aminooxyacetic acid (AOAA, 10(-4)-10(-3) mol/l), beta-alanine (10(-3)-10(-2) mol/l) and bicuculline (10(-5), 10(-4) mol/l) applications on the frog olfactory bulb (OB) were studied in vivo. The suppression of the orthodromic potential postsynaptic components evoked by a puff on the olfactory mucosa (OB input inhibition), or by single electrostimulation of the olfactory nerve (postsynaptic inhibition) was evaluated. 4-aminopyridine greatly reduced the OB input inhibition and strongly increased the postsynaptic inhibition. AOAA and bicuculline increased and beta-alanine slightly reduced the OB input inhibition. Clear-cut, simple alterations of the postsynaptic inhibition under the influence of the same drugs were not observed. The results confirm the hypothesis, that the OB input inhibition evoked by a puff on the olfactory mucosa may appear due to the release of GABA from glial cells and its binding with presynaptic GABAB-receptors in glomeruli.