The intracellular pathway of the acetylcholine-induced contraction in cat detrusor muscle cells.
1. The present study was aimed to investigate intracellular pathways involved in acetylcholine (ACh)-induced contraction in cat detrusor muscle cells 2. Contraction was expressed as per cent shortening of length of individually isolated smooth muscle cells obtained by enzymatic digestion. Dispersed intact and permeabilized cells were prepared for the treatment of drugs and antibody to enzymes, respectively. Using Western blot, we confirmed the presence of related proteins. 3. The maximal contraction to ACh was generated at 10(-11) M. This response was preferentially antagonized by M3 muscarinic receptor antagonist rho-fluoro-hexahydrosiladifenidol (rhoF-HSD) but not by the M1 antagonist pirenzepine and the M2 muscarinic receptor antagonist methoctramine. We identified G-proteins (Gq/11), (Gs), (G0), (Gi1), (Gi2) and (Gi3) in the bladder detrusor muscle. ACh-induced contraction was selectively inhibited by (Gq/11) antibody but not to other G subunit. 4. The phosphatidylinositol-specific phospholipase C (PI-PLC) inhibitor neomycin reduced ACh-induced contraction. However, the inhibitors of the phospholipase D, the phospholipase A2 and protein kinase C did not attenuate the ACh-induced contraction. ACh-induced contraction was inhibited by antibody to PLC-beta1 but not PLC-beta3 and PLC-gamma. Thapsigargin or strontium, which depletes or blocks intracellular calcium release, inhibited ACh-induced contraction. Inositol 1,4,5-triphosphate IP3 receptor inhibitor heparin reduced ACh-induced contraction. 5. These results suggest that in cat detrusor muscle contraction induced by ACh is mediated via M3 muscarinic receptor-dependent activation of Gq/11 and PLC-beta1 and IP3-dependent Ca(2+) release.
An
J Y
JY
Department of Pharmacology, College of Pharmacy, Chung Ang University, Seoul, 156-756, Republic of Korea.
Yun
H S
HS
Lee
Y P
YP
Yang
S J
SJ
Shim
J O
JO
Jeong
J H
JH
Shin
C Y
CY
Kim
J H
JH
Kim
D S
DS
Sohn
U D
UD
D000109:Acetylcholine / Q000494:pharmacology*; D000470:Alkaloids; D000818:Animals; D053119:Benzophenanthridines; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology; D002415:Cats; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D019204:GTP-Binding Proteins / Q000378:metabolism; D006493:Heparin / Q000494:pharmacology; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism; D008297:Male; D018727:Muscarinic Antagonists / Q000494:pharmacology; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects*; D009355:Neomycin / Q000494:pharmacology; D010617:Phenanthridines / Q000494:pharmacology; D010740:Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000037:antagonists & inhibitors / Q000502:physiology; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology; D013324:Strontium / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D010738:Type C Phospholipases / Q000037:antagonists & inhibitors / Q000378:metabolism; D001743:Urinary Bladder / Q000166:cytology / Q000187:drug effects*; D020245:p-Chloromercuribenzoic Acid / Q000494:pharmacology
D000470:Alkaloids; D053119:Benzophenanthridines; D015220:Calcium Channels; D004791:Enzyme Inhibitors; D053496:Inositol 1,4,5-Trisphosphate Receptors; D007527:Isoenzymes; D018727:Muscarinic Antagonists; D010617:Phenanthridines; D018160:Receptors, Cytoplasmic and Nuclear; D011976:Receptors, Muscarinic; D020245:p-Chloromercuribenzoic Acid; D019284:Thapsigargin; D006493:Heparin; C016299:chelerythrine; D011493:Protein Kinase C; D010740:Phospholipases; D010738:Type C Phospholipases; D019204:GTP-Binding Proteins; D009355:Neomycin; D000109:Acetylcholine; D002118:Calcium; D013324:Strontium