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NORADRENALINE IN THE GUINEA PIG ALIMENTARY CANAL: REGIONAL DISTRIBUTION AND SENSITIVITY TO DENERVATION AND RESERPINE
Author(s) -
Juorio A. V.,
Gabella G.
Publication year - 1974
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1974.tb04304.x
Subject(s) - myenteric plexus , reserpine , ileum , duodenum , medicine , caecum , jejunum , stomach , submucous plexus , endocrinology , cecum , large intestine , small intestine , submucosa , anatomy , biology , immunohistochemistry
The concentrations of noradrenaline, dopamine and 5‐hydroxytryptamine were studied in the stomach, duodenum, ileum, caecum (taenia coli), colon and rectum of the guinea pig. The wall of the alimentary canal was dissected into two fractions, one formed by the longitudinal muscle and myenteric plexus, the other formed by circular muscle, submucous plexus, submucosa and mucosa. In the longitudinal muscle‐myenteric plexus, the amount of noradrenaline was lower in the ileum (0.56 μg/g of fresh tissue), higher in the duodenum and caecum (0.75 μg/g and 0.82 μg/g respectively) and even higher in the stomach and rectum (0.85 μg/g and 0.91 μg/g). The highest value was found in the colon (1.33 μg/g), probably related to the occurrence of intramural adrenergic neurons. When extrinsic nerves to the ileum were damaged, the amount of noradrenaline in the corresponding ileal segment was reduced to less than 5 per cent within 3 days in both fractions of the wall. 6‐Hydroxydopamine (35 mg/kg intravenously) reduced to approx. one‐third the amount of noradrenaline in longitudinal muscle‐myenteric plexus of ileum and colon. Reserpine (1 mg/kg, subcutaneously injected 72 h‐earlier) reduced the amount of noradrenaline in the longitudinal muscle‐myenteric plexus of both ileum and colon to 0.01 μg/g. Doses of reserpine as small as 0.02 mg/kg were still effective in causing a great reduction in noradrenaline concentration. No difference in the effects on ileum and colon was observed.