The effect of some α2-adrenoceptor agonists and antagonists on gastrointestinal transit in mice: Influence of morphine, castor oil and glucose

B. H. Ali, A. A. Bashir

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14 Citations (Scopus)


1. The effects of graded doses of the α2-adrenoceptor agonists clonidine, tizanidine and BHT-920, and the α2-adrenoceptor antagonists yohimbine and idazoxan, on gastrointestinal transit were investigated in mice using the charcoal meal test. 2. The agonists produced significant and dose-dependent decreases in gastrointestinal transit, and the antagonists produced the opposite effect. In affecting the gastrointestinal transit, clonidine (1 mg/kg) was as effective as tizanidine (12 mg/kg) and BHT-920 (40 mg/kg), while yohimbine (2 mg/kg) was as effective as idazoxan (1 mg/kg). 3. Morphine (2, 4 and 8 mg/kg) significantly inhibited gastrointestinal transit. This effect was significantly reversed by the co-administration of yohimbine (2 mg/kg) and idazoxan (1 mg/kg). 4. The acute administration of glucose (5.04 g/kg i.p.) potentiated the inhibition of gastrointestinal transit produced by clonidine (1 mg/kg) and BHT-920 (40 mg/kg). Glucose treatment, however, had no significant effect on the increase in gastrointestinal transit induced by yohimbine (2 mg/kg) or idazoxan (1 mg/kg). 5. Castor oil (0.25 mL/mouse, orally) induced diarrhoea in saline-treated animals within about 45 min. Clonidine (1 mg/kg), tizanidine (12 mg/kg) and BHT-920 (40 mg/kg) delayed the occurrence of diarrhoea to 2.1, 1.2 and 1.4, respectively.

Original languageEnglish
Pages (from-to)1-6
Number of pages6
JournalClinical and Experimental Pharmacology and Physiology
Issue number1
Publication statusPublished - 1993



  • α-Agonists
  • α-Antagonists
  • Castor oil
  • Glucose
  • Intestinal transit
  • Morphine

ASJC Scopus subject areas

  • Physiology
  • Pharmacology (medical)
  • Pharmacology, Toxicology and Pharmaceutics(all)

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