The effects of physostigmine, L-arginine and NG-nitro-L-arginine methyl ester (L-NAME) on the mean arterial pressure of the rat.
The effects of physostigmine, L-arginine and NG-nitro-L-arginine methyl ester (L-NAME) were investigated in urethane-anaesthetized rats. The drugs were chosen because physostigmine has been known to produce an increase in peripheral adrenergic activity, whereas L-arginine and L-NAME have been known to modulate nitric oxide (NO) production. Slow infusion of L-arginine produced significant hypotension, but only in animals pretreated by physostigmine. L-NAME applied in the same way produced a slow developing increase in blood pressure, but not in animals pretreated by physostigmine. The pressor responses to physostigmine were potentiated if the drug was injected during infusion of L-NAME, and depressed if the drug was injected after stopping L-NAME infusion (in rats not pretreated with physostigmine). It is concluded that L-arginine-NO pathways act in vivo to oppose peripheral vasoconstrictor influences coupled with central cholinergically mediated activation of the adrenergic system, as produced by physostigmine. In this way, NO is part of a general mechanism for blood pressure regulation.
Prostran
M
M
Department of Pharmacology, Faculty of Medicine, Belgrade, Yugoslavia.
Varagić
V M
VM
Todorović
Z
Z
Jezdimirović
M
M
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007262:Infusions, Intravenous; D008297:Male; D009129:Muscle Tonus / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D019331:NG-Nitroarginine Methyl Ester / Q000008:administration & dosage / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D010830:Physostigmine / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar
D002800:Cholinesterase Inhibitors; D004791:Enzyme Inhibitors; D010830:Physostigmine; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester