Opposite effects of kappa-opioid agonists on gastric emptying of liquids and solids in dogs.
The influence of oral (p.o.) administration of kappa-(U-50488, tifluadom) and mu- (morphine, DAGO) opioid substances on gastric emptying of liquids and solids in a standard canned dog food meal was evaluated using a double-radiolabeled technique in dogs fitted with gastric cannulas. One hour after feeding, 28.6% +/- 3.6% (mean +/- SD) of the solid phase and 27.1% +/- 8.6% of the liquid phase of the meal had been emptied. Both U-50488 and tifluadom given orally (0.01-0.1 mg/kg) significantly increased (p less than 0.05) the 1-h emptying of the solid phase of the meal by 23.1%-49.6%. In contrast, both drugs significantly reduced emptying of liquids. These effects were not reproduced when similar doses were given intravenously. Oral administration of morphine or DAGO (0.01-0.1 mg/kg) did not affect gastric emptying, whereas an inhibited emptying of solids was observed for morphine at a higher dose (1 mg/kg p.o.). At a dose of 100 micrograms/kg i.v. both naloxone and MR 2266 (0.1 mg/kg) abolished the effects of orally administered U-50488 on gastric emptying of solids and liquids. It is concluded that kappa- but not mu-agonists act locally to alter gastric emptying of a standard meal in dogs, having opposite effects on solid and liquid phases. A selective local stimulation of kappa mucosal or submucosal receptors of the gastroduodenal area may explain such effects.
Gue
M
M
Department of Pharmacology, Institut National de la Recherche Agronomique, Toulouse, France.
Fioramonti
J
J
Honde
C
C
Pascaud
X
X
Junien
J L
JL
Bueno
L
L
D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D000284:Administration, Oral; D000821:Animal Feed; D000818:Animals; D001569:Benzodiazepines / Q000008:administration & dosage / Q000494:pharmacology*; D001575:Benzomorphans / Q000008:administration & dosage / Q000494:pharmacology*; D004285:Dogs / Q000502:physiology*; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects*; D007275:Injections, Intravenous; D009019:Morphinans / Q000494:pharmacology*; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009270:Naloxone / Q000008:administration & dosage / Q000494:pharmacology; D011759:Pyrrolidines / Q000008:administration & dosage / Q000494:pharmacology*
D001575:Benzomorphans; D004745:Enkephalins; D009019:Morphinans; D011759:Pyrrolidines; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D001569:Benzodiazepines; D009270:Naloxone; C027247:MR 2266; D019900:3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cyclohexyl)-benzeneacetamide, (trans)-Isomer; D009020:Morphine; C035470:tifluadom