[Effects of 2[p-(dimethylamino)styryl]pyridine methiodide on action potentials of sinoatrial node cells of rabbits].
The effects of 2[p-(dimethyl-amino)styryl]pyridine methiodide (DSPM) on the action potential of dominant pacemaker cells in sinoatrial nodes of rabbits were studied by microelectrode technique. DSPM 45 mumol/L decreased the slope of phase 4, the maximum rate of rise of the action potential and the action potential amplitude by 54% (P less than 0.01), 27% (P less than 0.05) and 13% (P less than 0.05), respectively, and increased the spontaneous sinus cycle length and action potential duration at 90% repolarization by 62 and 26% (P less than 0.01), respectively. These effects of DSPM were similar to that of nifedipine 3.9 mumol/L. The positive chronotropic effect of nicotinamide 33 mmol/L was completedly blocked by DSPM 45 mumol/L while that of isoprenaline 0.11 mumol/L was partially blocked by DSPM 45 mumol/L. The results suggest that DSPM may be a Ca2+ antagonist.
Li
D M
DM
Zhou
C M
CM
Wang
X W
XW
Zhang
K J
KJ
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002121:Calcium Channel Blockers; D005260:Female; D006801:Humans; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009536:Niacinamide / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D011726:Pyridinium Compounds / Q000494:pharmacology*; D011817:Rabbits; D012849:Sinoatrial Node / Q000166:cytology / Q000187:drug effects*
D002121:Calcium Channel Blockers; D011726:Pyridinium Compounds; C011786:2-(4-(dimethylamino)styryl)-1-methylpyridinium; D009536:Niacinamide; D009543:Nifedipine; D007545:Isoproterenol