Dorsal facial area of cat medulla; 5-HT2 action on glutamate release in regulating common carotid blood flow.
Serotonin (5-HT) may inhibit glutamate release in the dorsal facial area (DFA) of the medulla and decrease common carotid arterial (CCA) blood flow. We attempted to clarify which subtype(s) of 5-HT receptor was involved. A microdialysis probe was inserted in DFA. The concentration of glutamate in dialysates were determined by chromatography. Glutamate concentration was dose-dependently decreased by perfusion of 5-HT or DOI, a 5-HT2 agonist, but not by 5-CT, a 5-HT1 agonist. The 5-HT-induced decrease in glutamate was reversed by co-perfusion of ketanserin, a 5-HT2 antagonist, but not by propranolol, a 5-HT1 antagonist. CCA blood flow was decreased when 5-HT or DOI was perfused, and was reversed by co-perfusing ketanserin. In conclusion, 5-HT may inhibit glutamate release via 5-HT2 receptor in DFA, resulting in the reduction of CCA blood flow.
Kuo
J S
JS
Department of Education and Research and Geriatric Medical Center, Taichung Veterans General Hospital, Taiwan, ROC. jskuo@vghtc.vghtc.gov.tw
Li
H T
HT
Lin
N N
NN
Yang
C S
CS
Cheng
F C
FC
D000818:Animals; D017536:Carotid Artery, Common / Q000187:drug effects*; D002415:Cats; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism*; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects* / Q000378:metabolism; D017551:Microdialysis; D012701:Serotonin / Q000494:pharmacology*; D017366:Serotonin Receptor Agonists / Q000494:pharmacology
D017366:Serotonin Receptor Agonists; D012701:Serotonin; D018698:Glutamic Acid