Effects of Microiontophoretically Applied Some Different Transmitter Receptor Antagonists on the Evoked Response of “Pain” Units of Hypothalamic Paraventricular Nucleus / 第二军医大学学报

ABSTRACT

Effects of microiontophoretically applied transmitter receptor antagonists on the evoked response of “pain” units of PVN in rats by sciatic stimulation were observed. The results showed (l)The evoked response of 7 out of 38 PVN “pain” units could be blocked by atropine (7/38); 5 out of 27 by hexamethonium; 6 out of 31 by phentolamine (6/31); and 4 out of 25 by propranolol (4/25). Seventeen out of 52 were blocked by cyproheptadine (17/52), but 3 out of 52 were augmented by cyproheptadine (3/52). (2) The evoked response of the same “pain” unit could be blocked by two antagonists the evoked response of 2 out of 27 PVN “pain” units could be blocked by atropine and cyprohepadine; 3 out of 20 by hexamethonium and cyproheptadine; 2 out of 25 by prepamolol and cyproheptadine. These results suggest that the noxious somatic input to PVN involves 5-HT, cholinergic and adrenergic transmitter receptor mechanisms and that the convergence of various transmitter systems on PVN “pain” unit is indicated.