[Potentiation of procaine-induced local sensory block by verapamil in rats].
We have studied the effects of calcium-channel blocker, verapamil, on procaine-induced local sensory block. Standardized tail-flick (TF) test was used to investigate the duration and intensity of procaine-induced local conduction block in rats. After obtaining baseline TF latencies (mean; 3.3 sec), two 100 microliters of 0.4% procaine alone, a combination of 0.4% procaine and verapamil (100 micrograms, or 200 micrograms), or a large dose of verapamil (200 micrograms) were injected to the opposite sites of the tail base and TF test was performed every five minutes for 45 minutes. A large dose of verapamil showed no prolongation of TF latencies. The administration of 0.4% procaine alone produced a significant increase of TF latencies and the peak effect of % MPE (percent maximum possible effect) was demonstrated at 4 minutes after the drug injection (mean % MPE; 37.0%). Coadministration of 0.4% procaine and two doses of verapamil produced significant increases of % MPE in a dose-dependent fashion. It was concluded that sensory block by procaine of the peripheral nerves is potentiated by coadministration of calcium-channel blocker, verapamil.
Department of Anesthesiology, Sapporo Medical University, School of Medicine.
H
H
Ohmori
H
H
Iwasaki
K
K
Omote
M
M
Kawamata
T
T
Kawamata
M
M
Yamauchi
A
A
Namiki
D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D008297:Male; D009407:Nerve Block; D009431:Neural Conduction / Q000187:drug effects*; D011343:Procaine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time; D014700:Verapamil / Q000494:pharmacology*
D000779:Anesthetics, Local; D002121:Calcium Channel Blockers; D011343:Procaine; D014700:Verapamil