Mechanical responses evoked by nerve stimulation in gastric muscles of mouse lacking inositol trisphosphate receptor.
Alteration of mechanical responses elicited by transmural nerve stimulation (TNS) was investigated in pylorus muscle of stomach isolated from mutant mice lacking expression of IP, type-1 receptor. In wild and mutant mice. TNS inhibited spontaneous contractions and generated an off-response at the cessation. The effects of inhibitors of neurotransmission revealed that in wild mice, acetylcholine and nitric oxide were involved as excitatory and inhibitory mediators, respectively. In mutant mice, a lack of nitroxidergic component with associated attenuation of cholinergic transmission was found. The off-response was inhibited by apamin in both mice. In mutant mice, spantide-sensitive excitatory response appeared in the presence of apamin. Acetylcholine and substance P enhanced while noradrenaline and sodium nitroprusside inhibited spontaneous contractions, in both wild and mutant mice; the actions were weaker in mutant mice than in wild mice for any agonists. The results indicate that pylorus smooth muscles receive cholinergic excitatory and nitroxidergic and non-adrenergic non-cholinergic inhibitory projections, and a lack of IP, type-1 receptor results in an impairment of cholinergic and nitroxidergic components, with no alteration of non-adrenergic non-cholinergic inhibitory projections. In addition, the mutation induces a substance P projection which is not detected in wild mice.
Takano
H
H
Department of Physiology, Nagoya City University Medical School, Japan.
Imaeda
K
K
Yamamoto
Y
Y
Kato
K
K
Mikoshiba
K
K
Suzuki
H
H
D000109:Acetylcholine / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000700:Analgesics / Q000494:pharmacology; D000818:Animals; D001030:Apamin / Q000494:pharmacology; D015220:Calcium Channels / Q000235:genetics*; D002799:Cholinergic Fibers / Q000502:physiology; D004558:Electric Stimulation; D005746:Gastric Emptying / Q000187:drug effects / Q000502:physiology; D053496:Inositol 1,4,5-Trisphosphate Receptors; D051379:Mice; D008817:Mice, Mutant Strains; D009130:Muscle, Smooth / Q000294:innervation* / Q000502:physiology*; D009388:Neostigmine / Q000494:pharmacology; D009433:Neural Inhibition / Q000502:physiology; D009569:Nitric Oxide / Q000502:physiology; D009599:Nitroprusside / Q000494:pharmacology; D009638:Norepinephrine; D010277:Parasympathomimetics / Q000494:pharmacology; D010646:Phentolamine / Q000494:pharmacology; D011433:Propranolol; D011708:Pylorus / Q000294:innervation* / Q000502:physiology*; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics*; D013373:Substance P / Q000031:analogs & derivatives / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D000317:Adrenergic alpha-Antagonists; D000700:Analgesics; D015220:Calcium Channels; D053496:Inositol 1,4,5-Trisphosphate Receptors; D010277:Parasympathomimetics; D018160:Receptors, Cytoplasmic and Nuclear; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D001030:Apamin; D009569:Nitric Oxide; D013373:Substance P; D009388:Neostigmine; C042867:spantide; D011433:Propranolol; D000109:Acetylcholine; D009638:Norepinephrine; D010646:Phentolamine