[The characteristics of the binding of M-cholinergic blockers and beta-adrenoblockers by the brain synaptosomes of 15-day-old and adult rats].

Significant difference in values of basic parameters, Bmax and Kd which characterize binding of 3H-quinuclidynylbenzylate and 3H-dihydroalprenolol, specific blockers of m-cholino- and beta-adrenoreceptors, has been established for brain synaptosomes from 15-day and adult rats. It was shown that phospholipase A2 (1 microgram/ml), a membrane active component from the venom of the cobra Naja naja oxiana, reduced Bmax and Kd for binding 3H-quinuclidynylbenzylate and 3H-dihydroalprenolol by synaptosomes. It is suggested that functional modifications in membrane during animal development or induced by phospholipase A2 result in shifts in the specific activity of adreno- and cholinoreceptors and, as a result, in disturbances of adrenergic and cholinergic responses.