Effect of adrenergic neuron inhibitors on the vascular response to sympathetic nerve stimulation.

In anesthetized cats, the lumbar sympathetic trunk was stimulated, and the responses of the resistance and capacitance vessels of the hindlimb were recorded (by resistography and plethysmography, respectively). The drugs used were reserpine, methyldopa and bretylium tosylate. It was found that reserpine and methyldopa inhibit the response of the resistance vessels to a greater extent than that of the capacitance vessels, while bretylium tosylate has a greater effect on the transmission of constrictor impulses to the capacitance vessels. Reserpine mainly suppresses responses to low-frequency stimulation and bretylium tosylate--those to high-frequency stimulation, while methyldopa affects them to the same degree at all frequencies.