Olanzapine blocks the sympathetic and hyperthermic reactions due to cerebral injection of orexin A.
Since experiments regarding a possible relation between olanzapine and orexin A has been scarcely reported in international literature, this experiment tested the effect of olanzapine on the sympathetic and thermogenic effects induced by orexin A. The firing rates of the sympathetic nerves to interscapular brown adipose tissue (IBAT), along with IBAT, colonic temperatures and heart rate were monitored in urethane-anesthetized male Sprague-Dawley rats before an injection of orexin A (1.5 nmol) into the lateral cerebral ventricle and over a period of 150 min after the injection. The same variables were monitored in rats with an intraperitoneal administration of olanzapine (10mg/kg bw), injected 30 min before the orexin administration. The results show that orexin A increases the sympathetic firing rate, IBAT, colonic temperatures and heart rate. This increase is blocked by the injection of olanzapine. These findings indicate that olanzapine affects the complex reactions related to activation of orexinergic system.
Department of Experimental Medicine, Section of Human Physiology, Second University of Naples, Italy. marcellino.monda@unina2.it <marcellino.monda@unina2.it>
M
M
Monda
An
A
Viggiano
Al
A
Viggiano
R
R
Mondola
E
E
Viggiano
G
G
Messina
D
D
Tafuri
V
V
De Luca
D000818:Animals; D001569:Benzodiazepines / Q000008:administration & dosage*; D001831:Body Temperature / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006979:Hyperthermia, Induced; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D047908:Intracellular Signaling Peptides and Proteins / Q000008:administration & dosage* / Q000037:antagonists & inhibitors*; D008297:Male; D009479:Neuropeptides / Q000008:administration & dosage* / Q000037:antagonists & inhibitors*; D000077152:Olanzapine; D000068797:Orexins; D051381:Rats; D017207:Rats, Sprague-Dawley; D017367:Selective Serotonin Reuptake Inhibitors / Q000008:administration & dosage*; D013564:Sympathetic Nervous System / Q000187:drug effects*
D001569:Benzodiazepines; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000077152:Olanzapine; D000068797:Orexins; D017367:Selective Serotonin Reuptake Inhibitors; C000596229:HCRT protein, human