EFFECT OF BETHANECHOL, NEOSTIGMINE, METOCLOPRAMIDE, AND PROPRANOLOL ON MYOELECTRIC ACTIVITY OF THE ILEOCECOCOLIC AREA IN COWS

The effect of bethanechol, neostigmine, metoclopramide, and propranolo l on myoelectric activity of the ileum, cecum, and proximal loop of th e ascending colon was determined in 6 healthy Jersey cows implanted wi th 8 pairs of bipolar electrodes. Assigned at random, each cow receive d each of 5 treatments in 3-day intervals. The treatments included bet hanechol (0.07 mg/kg of body weight, SC), neostigmine (0.02 mg/kg, sc) , metoclopramide (0.15 mg/kg, IM), DL-propranolol (0.2 mg/kg, IM), and 0.9% sodium chloride (NaCl) solution (20 ml, SC). All drugs were admi nistered during early phase I of the migrating myoelectric complex in the ileum. Myoelectric activity was recorded for 4 hours after treatme nt, and data were analyzed for each hour separately. Bethanechol and n eostigmine significantly (P < 0.05) increased the number of cecocolic spikes per minute per electrode, duration of cecocolic spike activity (%), and number of cecocolic propagated spike sequences per 10 minutes , relative to NaCl, during 1 or more hours of the recording period. Th e effect of bethanechol was more pronounced on duration of spike activ ity and number of propagated spike sequences, whereas neostigmine main ly increased the number of (uncoordinated) spikes. Metoclopramide and propranolol had no significant effect on cecocolic myoelectric activit y, relative to NaCl. It was concluded that bethanechol and, less likel y, neostigmine at the dosage used in this study may be suitable for me dical treatment of cecal dilatation in cattle in which hypomotility of the cecum and proximal loop of the ascending colon has to be reversed . The potential advantage of bethanechol vs neostigmine for medical tr eatment of cecal dilatation is worth further evaluation.