The stimulatory effect of the boiled supernatant on cyclic AMP formation in synaptosomes from rat cerebral cortex.

The effect of the boiled supernatant on synaptosomal adenyl cyclase activity of rat cerebral cortex was investigated. The boiled supernatant markedly increased the accumulation of cyclic AMP in synaptosomes when added to adenyl cyclase system by a mechanism presumably unrelated to inhibition of cyclic AMP phosphod iesterase or adenosine triphosphatase. Magnesium ion was required for synaptosomal adenyl cyclase activity and its stimulation by the boiled supernatant. The result discerned by doubl reciprocal plots showed an increase in Vmax value of adenyl cyclase by addition of the boiled supernatant without significantly altering the affinity for substrate. The enzyme activity was not stimulated by dopamine, histamine and serotonin in either the absence and presence of the boiled supernatant.