Comparisons of neural and pacing activities in intestinal segments from W/W++ and W/W(V) mice.
We studied pacing and neurotransmission in longitudinal (LM) and circular muscle (CM) in intestine of W/W++ and W/W(V) mice. Electrical field-stimulation (EFS) of nerves in LM segments was more inhibitory in W/W(V) mice than in W/W++ mice. No inhibitory input to CM segments of W/W(V) mice was found. The EFS, after nerve block, entrained segments of both W/W++ and mutant mice with 10 ms pulses, and entrained those of mutant mice more readily at 1 and 3 ms pulses. Pacing with external electrodes did not depend on interstitial cells of Cajal in the myenteric plexus (ICC-MP). 2-Aminoethoxydiphenyl borate (2-APB), putative antagonist at IP3 receptors, store-operated channels and the Sacro-endoplasmic reticulum Ca2+ ATPase pump, reduced frequency and amplitudes of pacing of LM segments from W/W(V) mice as it did in BALB/c mice. Thus, its actions may not require ICC-MP. SKF 96365, a putative inhibitor of store-operated channels, reduced frequencies and amplitudes of intestinal segments in W/W++ mice at 10 or 30 micromol L-1. This resulted from blocking L-Ca2+-channels. Thus, no evidence was found that store-operated channels play a role in pacing. In LM segments of W/W(V), SKF 96365 had no effects on frequency of contractions. We conclude, results from models of severely reduced systems may not be applicable to intact ICC networks.
Daniel
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Department of Pharmacology, University of Alberta, Edmonton, Canada. edaniel@valberta.ca
Willis
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A
Cho
W J
WJ
Boddy
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D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D001896:Boron Compounds / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D066298:In Vitro Techniques; D007422:Intestines / Q000294:innervation* / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D009130:Muscle, Smooth / Q000502:physiology; D009197:Myenteric Plexus / Q000502:physiology; D009407:Nerve Block; D019335:Nitroarginine / Q000494:pharmacology; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics; D013045:Species Specificity; D013779:Tetrodotoxin / Q000494:pharmacology
D000779:Anesthetics, Local; D001896:Boron Compounds; D002121:Calcium Channel Blockers; D004791:Enzyme Inhibitors; D007093:Imidazoles; D019335:Nitroarginine; D013779:Tetrodotoxin; C109986:2-aminoethoxydiphenyl borate; D019009:Proto-Oncogene Proteins c-kit; C063159:1-(2-(3-(4-methoxyphenyl)propoxy)-4-methoxyphenylethyl)-1H-imidazole