Protein phosphorylation in respiring slices of guinea-pig cerebral cortex. Evidence for a role for noradrenaline and adenosine 3':5'-cyclic monophosphate in the increased phosphorylation observed on application of electrical pulses.

1. Exposure of slices of cerebral cortex from guinea pigs to electrical pulses for 10s or to noradrenaline, 5-hydroxytryptamine or histamine increases the rate of phosphorylation of unidentified proteins in the tissue; the increases in protein phosphorylation due to electrical pulses and noradrenaline were non-additive, whereas the increases due to pulses and 5-hydroxytryptamine or histamine were additive. 2. The stimulating effects of electrical pulses and noradrenaline on protein phosphorylation were antagonized by the beta-adrenergic blocking agents L-propranolol, dichloroisoprenaline, practolol and ICI 66082, but not by the alpha-adrenergic blocking agents, phentolamine and phenoxybenzamine. 3. The increase in protein phosphorylation associated with electrical pulses was antagonized by 10 mum-trifluoperazine and 0.5 mum-prostaglandin E1. 4. It is postulated that under the experimental conditions used the action of electrical pulses on protein phosphorylation is mediated by noradrenaline acting through a beta-adrenergic receptor mechanism probably involving adenylate cyclase.