Effect of histamine on regional cerebral blood flow of the parietal lobe in rats.
Histamine is a powerful modulator that regulates blood vessels and blood flow. The effect of histamine on the extracortical vessels has been well described, while much less is known about the effect of histamine on intracortical vessels. In this study, we investigated the effect of histamine on regional cerebral blood flow in rat parietal lobe with laser Doppler flowmetry. The pharmacological characteristics of distinct ways (intracerebroventricular injection, intraperitoneal injection, and cranial window infusion) in applying histamine to the brain were also obtained and compared. Histamine applied in three ways all produced a decrease of rCBF in parietal lobe in a concentration-dependent manner. Cranial window infusion was the most effective way and intraperitoneal injection of L-histidine was the most ineffective, although it is a simple and applied way. To determine which type of receptor takes part in the vessel contraction induced by histamine, H1 receptor antagonist, diphenhydramine, and H2 receptor antagonist, cimetidine, were applied, respectively, before histamine administration. When the injection of cimetidine was conducted in advance, histamine still resulted in a decrease of infusion amount; while the injection of diphenhydramine was conducted in advance, the infusion of blood amount wasn't changed. These findings indicated that histamine could result in a reduction of rCBF in the rat parietal lobe and this effect of histamine may attribute partly to its combination with H1 receptor.
Yang
Peng-Bo
PB
Institute of Neurobiology, Environment and Genes Related to Diseases Key Laboratory of Education Ministry, Xi'an Jiaotong University College of Medicine, 76 Yanta Western Road, Xi'an, Shaanxi, 710061, People's Republic of China.
Chen
Xin-Lin
XL
Zhao
Jian-Jun
JJ
Zhang
Jian-Shui
JS
Zhang
Jun-Feng
JF
Tian
Yu-Mei
YM
Liu
Yong
Y
D000818:Animals; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D002927:Cimetidine / Q000494:pharmacology; D004155:Diphenhydramine / Q000494:pharmacology; D006632:Histamine / Q000008:administration & dosage / Q000494:pharmacology*; D006634:Histamine H1 Antagonists / Q000494:pharmacology; D006635:Histamine H2 Antagonists / Q000494:pharmacology; D006639:Histidine / Q000008:administration & dosage; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D017078:Laser-Doppler Flowmetry; D008297:Male; D010296:Parietal Lobe / Q000098:blood supply* / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects
D006634:Histamine H1 Antagonists; D006635:Histamine H2 Antagonists; D006639:Histidine; D002927:Cimetidine; D006632:Histamine; D004155:Diphenhydramine