JaLCDOI 10.18926/AMO/31027
FullText URL fulltext.pdf
Author Jin, Ji-Guang| Neya, Toshiaki| Takaki, Miyako|
Abstract <p>To study the polarity of the efferent pathway of the myenteric plexus, recordings were made of the mechanical activity of the longitudinal muscle of isolated guinea-pig ileal segments upon stimulation with an electrical field around the myenteric plexus contained within strips of longitudinal muscle (LM-MP) continuous with each end of ileal segment. The amplitude of the contractile response to stimulation of the anal LM-MP was always larger than that to the oral LM-MP. After cholinergic and adrenergic transmission was suppressed by atropine (10 microM) and guanethidine (1 microM), and the tone of the segment was enhanced by histamine (1 microM), the LM-MP stimulation produced non-cholinergic, non-adrenergic (NCNA) ascending contraction and NCNA descending relaxation. The NCNA contraction, but not the NCNA relaxation, was abolished or reduced by desensitization to substance P. The present results suggest that the NCNA innervation of the myenteric plexus participates in the polar effects observed in the guinea-pig ileum, that the NCNA excitatory response may be mediated at least in part by myenteric substance P neurons, and that the NCNA inhibitory response is mediated by non-adrenergic neurons.</p>
Keywords ileal motility intrinsic reflex myenteric plexus substance P guinea pig
Amo Type Article
Published Date 1988-06
Publication Title Acta Medica Okayama
Volume volume42
Issue issue3
Publisher Okayama University Medical School
Start Page 129
End Page 136
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 2456670
Web of Science KeyUT A1988P034000002
JaLCDOI 10.18926/AMO/30860
FullText URL fulltext.pdf
Author Takaki, Miyako| Jin, Ji-Guang| Nakayama, Sosogu|
Abstract <p>Effects of capsaicin on the circular muscle motility of the isolated guinea-pig ileum were investigated. Capsaicin produced a contraction followed by a relaxation of the circular muscle. Both responses were easily desensitized. As the late relaxation response was not sufficiently intense to be analyzed, the inhibitory effect of capsaicin on substance P-induced contractions was explored. Capsaicin abolished the substance P-induced contractions. This inhibitory effect was not affected by tetrodotoxin, and the effect was desensitized. Therefore, all effects of capsaicin on circular muscle motility seem to be due to the release of sensory neuropeptides, similarly to those elicited in the longitudinal muscle.</p>
Keywords calcitonin gene-related peptide capsaicin circular muscle intestine substance P
Amo Type Article
Published Date 1989-12
Publication Title Acta Medica Okayama
Volume volume43
Issue issue6
Publisher Okayama University Medical School
Start Page 353
End Page 357
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 2483022
Web of Science KeyUT A1989CG27400006
JaLCDOI 10.18926/AMO/30461
FullText URL fulltext.pdf
Author Takaki, Miyako| Jin, Ji-Guang| Nakayama, Sosogu|
Abstract <p>Capsaicin-sensitive and hexamethonium-insensitive contractile and relaxatory motor responses of circular muscle induced by mesenteric nerve stimulation were studied. Desensitization to substance P or to neurokinin A, or the substance P antagonist, spantide largely reduced the initial contractile response. Desensitization to calcitonin gene-related peptide moderately reduced the late prolonged relaxation response. These results indicate that both responses of the circular muscle to mesenteric nerve stimulation may be attributed to a release of neuropeptides evoked by the 'efferent' stimulation of capsaicin-sensitive sensory nerves.</p>
Keywords calcitonin gene-relatsd peptide capsaicin ileal motility mesenteric nerve substance P
Amo Type Article
Published Date 1990-06
Publication Title Acta Medica Okayama
Volume volume44
Issue issue3
Publisher Okayama University Medical School
Start Page 135
End Page 139
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 1696423
Web of Science KeyUT A1990DM18300004
JaLCDOI 10.18926/AMO/30444
FullText URL fulltext.pdf
Author Takaki, Miyako| Mizutani, Masatoshi| Jin, Ji-Guang| Nakayama, Sosogu|
Abstract <p>In the present study, tryptamine produced a slow hyperpolarization in a few neurons other than a slow depolarization in myenteric neurons of the isolated guinea-pig ileum. Neither the adrenergic neuron blocker, guanethidine nor the 5-hydroxytryptamine uptake inhibitor, zimelidine, which can inhibit the release of 5-hydroxytryptamine from enteric neurites induced by tryptamine (M. Takaki et al. (1985) Neuroscience 16, 223-240), affected this slow hyperpolarization. Therefore, it was concluded that the slow hyperpolarization induced by tryptamine in myenteric neurons was not mediated via the release of 5-hydroxytryptamine or noradrenaline. It might be possible that the hyperpolarization was induced by a direct action of tryptamine on myenteric neurons per se.</p>
Keywords intracelluar recording tryptamine hyperpolarization myenteric neurons
Amo Type Article
Published Date 1990-04
Publication Title Acta Medica Okayama
Volume volume44
Issue issue2
Publisher Okayama University Medical School
Start Page 87
End Page 91
ISSN 0386-300X
NCID AA00508441
Content Type Journal Article
language 英語
File Version publisher
Refereed True
PubMed ID 2141967
Web of Science KeyUT A1990DE10000005