Calcium dependent K-channels in guinea pig and human urinary bladder.
This study provides evidence for the presence of large conductance Ca(2+)-dependent K-channels in guinea pig and human urinary bladder smooth muscle. A23187, a Ca(2+)-ionophore, increased charybdotoxin and iberiatoxin sensitive 42K efflux in human urinary bladder smooth muscle cells, suggesting that large conductance Ca(2+)-dependent K-channels are present in these cells. NS004, a large conductance Ca(2+)-dependent K-channel opener, relaxed guinea pig bladder strips precontracted with 15 mM KCl which is inhibited by iberiatoxin. In addition, NS004 also evoked an iberiatoxin sensitive increase in 86Rb/42K efflux in guinea pig and human urinary bladder smooth muscle cells, demonstrating that NS004 activates large conductance Ca(2+)-dependent K-channels to achieve its relaxation effect in the bladder.
Trivedi
S
S
Department of Pharmacology and Medicinal Chemistry, Zeneca Pharmaceuticals Group, Zeneca Inc., Wilmington, DE 19897, USA.
Potter-Lee
L
L
Li
J H
JH
Yasay
G D
GD
Russell
K
K
Ohnmacht
C J
CJ
Empfield
J R
JR
Trainor
D A
DA
Kau
S T
ST
D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D018999:Charybdotoxin; D002733:Chlorophenols / Q000494:pharmacology; D004553:Electric Conductivity; D006168:Guinea Pigs; D006801:Humans; D009126:Muscle Relaxation / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D010455:Peptides / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D011189:Potassium Chloride / Q000494:pharmacology; D012414:Rubidium Radioisotopes; D012604:Scorpion Venoms / Q000494:pharmacology; D001743:Urinary Bladder / Q000187:drug effects / Q000502:physiology*
D001562:Benzimidazoles; D002733:Chlorophenols; D010455:Peptides; D015221:Potassium Channels; D012414:Rubidium Radioisotopes; D012604:Scorpion Venoms; D018999:Charybdotoxin; D000001:Calcimycin; C083230:NS 004; D011189:Potassium Chloride; C064719:iberiotoxin; D002118:Calcium