Effects of hemicholinium-3 or physostigmine on rat brain noradrenaline depletion induced by foot shocks.

Foot shocks applied to the rat on a grid floor caused brain noradrenaline depletion. Hemicholinium-3 injected intracerebroventricularly (i.c.v.) blocked the noradrenaline depletion and this blockade was reversed by choline (i.c.v.). Physostigmine (i.c.v.) had different effects according to the age of the rats: "young" and "intermediate" groups were depleted but not "adult" groups. Physostigmine plus shocks caused depletion only in "young" groups; the depletion not shown in "intermediat" groups, reappeared after pretreatment with alpha-methyl-p-tyrosine. It is concluded that there probably is a relationship between cholinergic and adrenergic neural systems when brain noradrenaline id depleted by shocks.