Effects of TMB-8 on constriction of pial arteries in rats.
OBJECTIVE
To study the effects of 8-(N,N-diethylamino)-n-octyl-3,4,5-trimethoxybenzoate (TMB-8) on constriction of pial arteries (PA).


METHODS
The change of PA in rats was observed continuously and directly through cranial window using microcircular image-shearing system.


RESULTS
Nimodipine (Nim) 1 mumol.L-1 produced dilatation of PA immediately and the maximal response occurred in 2 min. But the diameter was not changed by TMB-8 50 mumol.L-1. PA diameter decreased immediately after the application of CSF containing KCl. TMB-8 25, 50 mumol.L-1 apparently inhibited KCl-induced PA constriction. When persistent constriction was evoked by 5-HT, diameter of PA were increased in a concentration-dependent manner after application of TMB-8, which was inhibited by N omega-nitro-L-arginine methyl ester (L-NAME).


CONCLUSIONS
TMB-8 inhibited the contraction induced by 5-HT or KCl in cerebral artery, probably via its calcium antagonization and nitric oxide release.
Department of Pharmacology, Nanjing Medical University, Nanjing 210029, China. BinWang@njmu.edu.cn
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Wang
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D000818:Animals; D001158:Arteries / Q000187:drug effects; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D005260:Female; D005707:Gallic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology*; D008297:Male; D010841:Pia Mater / Q000098:blood supply*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014661:Vasoconstriction / Q000187:drug effects*
D002121:Calcium Channel Blockers; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid