[Comparative characteristics of the reactions of small intestine vessels to neurogenic influences and catecholamine application].

In acute experiments on cats using resistography and extracorporeal venous reservoir, responses of the small intestine's arterial and venous vessels were studied by means of successive pressor reflexes, electrical stimulation of the splanchnic nerve (1-80/sec) and i.a. administration of different doses of adrenaline (A) and noradrenaline (NA). The maximal constrictor responses of the vessels occurred mainly on the 10/sec stimulation; A induced mainly an increase in the perfusion pressure and venous outflow whereas NA induced chiefly an increase in the perfusion pressure and diminishing of the venous outflow. In pressor reflexes, low-frequency stimulation of the splanchnic nerve (2-5/sec) and i.a. administration of A, the venous vessels actualise a considerably greater part of the possible neurogenic constriction as compared to the arteries. The constrictor responses of the arteries in the pressor reflexes under study are equal to those on either left splanchnic nerve stimulation (1-2.5/sec) or i.a. administration of A or NA in doses lower than 0.5-1.0 mcg. The constrictor responses of the venous vessels in these conditions are equal to those on either left splanchnic nerve stimulation (3-8/sec) or i.a. administration of A in doses 0.5-1.0 mcg.