[Peripheral mechanisms of the responses of small intestine capacitance vessels to noradrenaline].

Noradrenalin was shown to elicit either constrictory or dilatory responses depending on the initial level of venous pressure (10-15 mm Hg or 0 and 25 mm Hg) in the capacitance vessels of the cat small intestine. Blockade of beta-adrenoreceptors with propranolol has no effect on the capacitance vessels responses. Blockade of alpha-adrenoreceptors with dihydroergotoxin makes noradrenaline to elicit dilatory responses only, their magnitude depending on the initial level of venous pressure: more obvious responses at 10-15 mm Hg, less obvious those - at 0 and 25 mm Hg.