Abstract
The effects of histamine and related compounds on regional cerebral blood flow (rCBF) in the hippocampus of conscious rats were studied. Intracerebroventricular injection of histamine caused a dose-dependent increase in rCBF in the hippocampus, and similar findings were observed with not only the H1 agonist, 2-thiazolylethylamine, but also the H2 agonist, dimaprit. Intraperitoneal injection of L-histidine also resulted in an increase in rCBF in the hippocampus, in parallel with elevation of histamine content in the brain. The increase in rCBF in the hippocampus induced by L- histidine was antagonized by both H1 and H2 antagonists (diphenhydramine, pyrilamine and zolantidine). In addition, when both antagonists were injected simultaneously, an additive effect was observed in antagonism of the L- histidine-induced increase in rCBF. L-Histidine caused no marked changes in blood pressure even at a dose of 1,500 mg/kg, which showed an increase in rCBF in the hippocampus. These results indicate that histamine elicited an increase in rCBF via both H1 and H2 receptors.
| Original language | English |
|---|---|
| Pages (from-to) | 613-617 |
| Number of pages | 5 |
| Journal | Methods and Findings in Experimental and Clinical Pharmacology |
| Volume | 21 |
| Issue number | 9 |
| Publication status | Published - Dec 1 1999 |
Keywords
- H Agonist
- H Agonist
- Histamine
- L-Histidine
- Regional cerebral blood flow
ASJC Scopus subject areas
- Pharmacology
- Pharmacology (medical)