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Modification by 6‐hydroxydopamine (6‐OHDA) of the inhibition of extrinsic rumen contractions in sheep produced by beta‐endorphin
Author(s) -
KANIA B. F.,
MIERT A. S. J. P. A. M.
Publication year - 1992
Publication title -
journal of veterinary pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.527
H-Index - 60
eISSN - 1365-2885
pISSN - 0140-7783
DOI - 10.1111/j.1365-2885.1992.tb00984.x
Subject(s) - rumen , hydroxydopamine , medicine , endocrinology , chemistry , beta endorphin , motility , beta (programming language) , biology , dopamine , biochemistry , genetics , dopaminergic , fermentation , computer science , programming language
In sheep, beta‐endorphin (1 and 2 μg/kg) administered into the third cerebral ventricle caused a significant inhibition of the frequency of rumen contractions. The amplitude of the first rumen contractions, following immediately after the end of infusion, and the average amplitude of primary rumen contractions, were inhibited. Beta‐endorphin caused general psychomotor excitability. These results suggest that an inhibitory p and 6 opioid system is involved in the control of forestomach motility and general behaviour in sheep. All effects of beta‐endorphin were completely prevented by i.c.v. 6‐hydroxydopamine (6‐OHDA, 18.2 μg/kg) pre‐treatment. These results suggest that beta‐endorphin‐induced inhibition of rumen motility is due to central noradrenergic system activation. The exact location of this noradrenergic system remains to be determined.