[Antagonistic effects of dextromethorphan on vasoconstriction of phencyclidine in vitro].
Bioassay and spectrophotofluorometry were used to study the antagonistic effect of dextromethorphan (DM) on phencyclidine (PCP) vasoconstriction in rabbit ear artery. DM (5 mumols.L-1) antagonized enhancement of PCP, N-[1-(2-thienyl) cyclohexyl] piperidine (TCP) and dizocilpine maleate (MK-801) (5 mumols.L-1) on electrical stimulation-induced vasoconstriction by 86 +/- 18%, 84 +/- 17%, and 86 +/- 18%, respectively (n = 6, P less than 0.01), but had no obvious bioactivity itself at the same concentration. DM (1, 2.5, and 5 mumols.L-1) inhibited the PCP effect and reduced the maximal effect of PCP with pD2' = 5.3 +/- 0.3 (n = 4). The contents of norepinephrine (NE) in control, PCP, and DM + PCP groups were 5 +/- 6, 12 +/- 8, and 5 +/- 6 ng.ml-1, respectively (n = 9). PCP (10 mumols.L-1) increased the NE release (P less than 0.05) but DM (10 mumols.L-1) inhibited it (P less than 0.01). The results suggest DM may be a noncompetitive blockader for PCP receptors.
Bao
W L
WL
Department of Neurobiology, Shanghai Medical University, China.
Sun
F Y
FY
Zheng
F C
FC
Zhang
A Z
AZ
D000818:Animals; D001681:Biological Assay; D003915:Dextromethorphan / Q000494:pharmacology*; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D009638:Norepinephrine / Q000378:metabolism; D010622:Phencyclidine / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D011817:Rabbits; D014661:Vasoconstriction / Q000187:drug effects*
D016291:Dizocilpine Maleate; D003915:Dextromethorphan; C012058:tenocyclidine; D010622:Phencyclidine; D009638:Norepinephrine