Brain phospholipase C-diacylglycerol lipase pathway is involved in vasopressin-induced release of noradrenaline and adrenaline from adrenal medulla in rats.
Recently, we reported that intracerebroventricularly (i.c.v.) administered arginine-vasopressin evokes the release of noradrenaline and adrenaline from adrenal medulla by brain thromboxane A2-mediated mechanisms in rats. These results suggest the involvement of brain arachidonic acid in the vasopressin-induced activation of the central adrenomedullary outflow. Arachidonic acid is released mainly by two pathways: phospholipase A2 (PLA2)-dependent pathway; phospholipase C (PLC)- and diacylglycerol lipase-dependent pathway. In the present study, therefore, we attempted to identify which pathway is involved in the vasopressin-induced release of both catecholamines from adrenal medulla using urethane-anesthetized rats. Vasopressin (0.2 nmol/animal, i.c.v.)-induced elevation of plasma noradrenaline and adrenaline was dose-dependently reduced by neomycin [0.28 and 0.55 micromol (250 and 500 microg)/animal, i.c.v.] and 1-[6-[[(17beta)-3-methoxyestra-1,3,5(10)-trien-17-yl]amino]hexyl]-1H-pyrrole-2,5-dione (U-73122) [5 and 10 nmol (2.3 and 4.6 microg)/animal, i.c.v.] (inhibitors of PLC), and also by 1,6-bis(cyclohexyloximinocarbonylamino)hexane (RHC-80267) [1.3 and 2.6 micromol (500 and 1000 microg)/animal, i.c.v.] (an inhibitor of diacylglycerol lipase). On the other hand, mepacrine [1.1 and 2.2 micromol (500 and 1000 microg)/animal, i.c.v.] (an inhibitor of PLA2) was largely ineffective on the vasopressin-induced elevation of plasma catecholamines. These results suggest that vasopressin evokes the release of noradrenaline and adrenaline from adrenal medulla by the brain PLC- and diacylglycerol lipase-dependent mechanisms in rats.
Shimizu
Takahiro
T
Department of Neuropharmacology, Program of Neural Integration, Kochi Medical School, Kochi University, Nankoku, Kochi 783-8505, Japan.
Okada
Shoshiro
S
Yamaguchi-Shima
Naoko
N
Yokotani
Kunihiko
K
D000313:Adrenal Medulla / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D001921:Brain / Q000201:enzymology*; D002395:Catecholamines / Q000097:blood / Q000378:metabolism*; D003512:Cyclohexanones / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000097:blood / Q000378:metabolism; D004963:Estrenes / Q000494:pharmacology; D007276:Injections, Intraventricular; D008071:Lipoprotein Lipase / Q000037:antagonists & inhibitors / Q000378:metabolism; D008297:Male; D009355:Neomycin / Q000494:pharmacology; D009638:Norepinephrine / Q000097:blood / Q000378:metabolism; D010741:Phospholipases A / Q000037:antagonists & inhibitors; D054467:Phospholipases A2; D011760:Pyrrolidinones / Q000494:pharmacology; D011796:Quinacrine / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D013997:Time Factors; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism; D014667:Vasopressins / Q000494:pharmacology*
D002395:Catecholamines; D003512:Cyclohexanones; D004963:Estrenes; D011760:Pyrrolidinones; D014667:Vasopressins; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C036535:1,6-bis(cyclohexyloximinocarbonyl)hexane; D010741:Phospholipases A; D008071:Lipoprotein Lipase; D054467:Phospholipases A2; D010738:Type C Phospholipases; D011796:Quinacrine; D009355:Neomycin; D009638:Norepinephrine; D004837:Epinephrine