The effects of intracoeliac injections of alpha-adrenergic agonists and veratridine on reticuloruminal motility and the evocation of rumination in sheep.
The ability of alpha-2 adrenoreceptor agonists and veratridine to evoke rumination and to modify reticular motility in adult Suffolk-cross sheep when injected by close-arterial injection into the forestomach was investigated. The specific alpha-2 adrenoreceptor agonists, xylazine and medetomidine, evoked rumination and increased reticular motility. The Na+ channel activator veratridine also evoked rumination and dramatically increased reticular motility. In contrast, injection of the alpha-1 adrenoreceptor agonist, phenylephrine, was ineffectual in evoking rumination and resulted in reduced reticular motility. It is concluded that the evocation of rumination by alpha-2 adrenergic agonists and veratridine is probably due to the activation of sensory nervous receptors (epithelial receptors) located in the reticulorumen.
Campion
D P
DP
Department of Veterinary Physiology and Biochemistry, U.C.D. Veterinary College, Dublin.
Leek
B F
BF
D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D003000:Clonidine / Q000008:administration & dosage / Q000494:pharmacology; D005769:Gastrointestinal Motility / Q000187:drug effects* / Q000502:physiology; D007093:Imidazoles / Q000008:administration & dosage / Q000494:pharmacology; D007269:Injections, Intra-Arterial / Q000662:veterinary; D020926:Medetomidine; D010656:Phenylephrine / Q000008:administration & dosage / Q000494:pharmacology; D012417:Rumen / Q000187:drug effects / Q000502:physiology*; D012756:Sheep / Q000502:physiology*; D014701:Veratridine / Q000008:administration & dosage / Q000494:pharmacology*; D014991:Xylazine / Q000008:administration & dosage / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D007093:Imidazoles; D010656:Phenylephrine; D014991:Xylazine; D014701:Veratridine; D003000:Clonidine; D020926:Medetomidine