[Effect of strychnine, hydrastine and apamin on synaptic transmission in smooth muscle cells].

The effects of strychnine, hydrastine and apamine on nervemuscle transmission in guinea pig stomach and taenia coli were studied. Hydrastine and strychnine produced an increase in non-adrenergic IPSPs of smooth muscle cells. Under apamine action IPSPs and hyperpolarization caused by exogenous ATP were reversibly blocked and non-cholinergic EPSPs appeared. ATP caused depolarization of the cell membrane in this condition. Consequently, apamine is a specific (postsynaptic) blocking agent of non-adrenergic inhibition and ATP obviously mediates both non-adrenergic inhibition and non-cholinergic synaptic excitation of smooth muscle cells observed in our experiments.