Species differences in the cardiovascular responses to histamine H3 receptor activation.
Potential species differences in cardiovascular responses to histamine H3 receptor activation were studied in the conscious guinea pig, rabbit, normotensive rat and the spontaneously hypertensive rat. R-alpha-Methylhistamine (100 micrograms/kg i.v.) decreased blood pressure in both the guinea pig and the rabbit. In the guinea pig, R-alpha-methylhistamine decreased heart rate, whereas in the rabbit it produced a tachycardia. In the normotensive rat and spontaneously hypertensive rat, R-alpha-methylhistamine (100 micrograms/kg i.v.) had no effect on blood pressure and heart rate. The cardiovascular action of R-alpha-methylhistamine in the guinea pig and rabbit was blocked by pretreatment with thioperamide (1.0 mg/kg i.v.) but not by chlorpheniramine (0.3 mg/kg i.v.) or cimetidine (3.0 mg/kg i.v.), respectively. These results indicate species differences in cardiovascular responses to histamine H3 receptor activation.
CNS Pharmacology, Schering-Plough Research Institute, Kenilworth, NJ 07033.
R L
RL
McLeod
S B
SB
Gertner
J A
JA
Hey
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002927:Cimetidine / Q000494:pharmacology; D006168:Guinea Pigs; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects; D017442:Histamine Agonists / Q000494:pharmacology; D006633:Histamine Antagonists; D008297:Male; D008761:Methylhistamines / Q000494:pharmacology; D010880:Piperidines / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D011918:Rats, Inbred SHR; D017207:Rats, Sprague-Dawley; D018100:Receptors, Histamine H3 / Q000378:metabolism*; D013045:Species Specificity
D017442:Histamine Agonists; D006633:Histamine Antagonists; D008761:Methylhistamines; D010880:Piperidines; D018100:Receptors, Histamine H3; C069357:alpha-methylhistamine; D002927:Cimetidine; C052075:thioperamide