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Effect of butorphanol on equine antroduodenal motility
Author(s) -
MERRITT A. M.,
CAMPBELLTHOMPSON MARTHA L.,
LOWREY S.
Publication year - 1989
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1989.tb05649.x
Subject(s) - butorphanol , tolazoline , anesthesia , antagonist , duodenum , medicine , migrating motor complex , (+) naloxone , opioid antagonist , receptor
Summary Six healthy six to eight‐month‐old horses were surgically prepared with Ag bipolar electrodes sutured to the gastric antrum and duodenum. Leads from the electrodes were exteriorised through a stab incision in the flank. During experimental sessions the horses were lightly restrained in stocks and electrode leads were connected to a physiograph to record antroduodenal myoelectrical activity. Intravenous (iv) injection of 0.05 mg/kg bodyweight (bwt) of the opioid agonist/antagonist, butorphanol was followed within 2 to 3 mins by a normal appearing period of repetitive spike activity, or phase III, of the migrating motor complex (MMC) on the duodenum. This was followed by a period of no spike activity, or phase I, of the MMC and then resumption of intermittent spike activity, or phase II, of normal duration. Pre‐treatment with 15 μg/kg bwt of the non‐selective opioid antagonist, naloxone, or with 1 mg/kg bwt of the (α 2 ‐adrenergic antagonist, tolazoline, did not block the myoelectrical response to butorphanol. It was concluded that a dose of butorphanol that has effective analgesic effects in a colicky horse resets the antroduodenal MMC without causing undesirable effects on antroduodenal motility. This particular effect of butorphanol might not be mediated by either a 2 ‐adrenergic or opioid receptors, although the latter question needs further investigation.