Effects of tetrandrine on action potentials and afterhyperpolarization potentials in toad dorsal root ganglia.
Intracellular recordings were obtained from the cytosome of type A primary afferents in the isolated toad dorsal root ganglia (DRG) preparations. Bath application of Ca2+ 8.0 mmol.L-1 led to prolong action potential duration of repolarization 100% (APD100) by 23%, afterhyperpolarization potential duration of depolarization 50% (AHPD50) by 46%, and increase afterhyperpolarization potential amplitude (AHPA) by 40%. Verapamil 3 mumol.L-1 shortened the APD100 by 7% and the AHPD50 by 13%, and reduced the AHPA by 17%. The effects of Tet 3-100 mumol.L-1 consisted of APD and AHPD50 shortening and AHPA reduction in concentration-dependent manner. Tet 100 mumol.L-1, APD100 was shortened by 16%, AHPD50 by 18%, and AHPA was reduced by 20%. The results suggested that the effects of Tet may be related to its Ca2+ channel blockade in DRG.
Zeng
W Z
WZ
Department of Pharmacology, Nanjing Medical College, China.
Liu
T P
TP
D000200:Action Potentials / Q000187:drug effects; D000470:Alkaloids / Q000494:pharmacology*; D000818:Animals; D044182:Benzylisoquinolines; D002023:Bufo bufo; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002122:Calcium Chloride / Q000494:pharmacology; D005260:Female; D005727:Ganglia, Spinal / Q000187:drug effects* / Q000502:physiology; D008297:Male; D014700:Verapamil / Q000494:pharmacology
D000470:Alkaloids; D044182:Benzylisoquinolines; D002121:Calcium Channel Blockers; C009438:tetrandrine; D014700:Verapamil; D002122:Calcium Chloride