Suppression of the carbachol-activated nonselective cationic current by antibody against alpha subunit of Go protein in guinea-pig gastric myocytes.
In this study, we investigated which subtype of GTP-binding protein (G protein) is related to muscarinic activation of nonselective cation (NSC) channels in gastric smooth muscle. Inward cationic current was activated by the application of 50 microM carbachol (ICCh) at a holding potential of -60 mV with the same CsCl-rich solution in both pipette and bath. The same cationic current as ICCh was slowly activated by the dialysis of guanosine 5'-O-(3-thiotriphosphate) (GTP[gamma-S]) through the pipette. Since it is known that pertussis toxin pretreatment can block ICCh, antibodies (Abs) against Galpha,i (anti-Galpha,i) or Galpha,o (anti-Galpha,o) were tested. Activation of ICCh was blocked by the addition of anti-Galpha,o. However, anti-Galpha,i Abs had no significant effect on ICCh. The expression of Galpha,o in guinea-pig gastric smooth muscle was confirmed by Western immunoblot analysis. These results suggest that Go-type protein may mediate signals from the muscarinic receptor to NSC channel in guinea-pig gastric myocytes.
Kim
Y C
YC
Department of Physiology and Biophysics, Seoul National University College of Medicine, 28 Yongon-Dong, Chongno-Gu, Seoul 110-799, Korea.
Kim
S J
SJ
Sim
J H
JH
Cho
C H
CH
Juhnn
Y S
YS
Suh
S H
SH
So
I
I
Kim
K W
KW
D000818:Animals; D000906:Antibodies / Q000276:immunology; D002217:Carbachol / Q000494:pharmacology*; D005260:Female; D019204:GTP-Binding Proteins / Q000276:immunology / Q000502:physiology*; D006168:Guinea Pigs; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects* / Q000276:immunology; D008297:Male; D008564:Membrane Potentials; D018721:Muscarinic Agonists / Q000494:pharmacology*; D009130:Muscle, Smooth / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D018408:Patch-Clamp Techniques; D013270:Stomach / Q000166:cytology / Q000187:drug effects* / Q000502:physiology
D000906:Antibodies; D007473:Ion Channels; D018721:Muscarinic Agonists; D002217:Carbachol; D019204:GTP-Binding Proteins