title: Turmeric active substance, curcumin, enhanced apomorphine-induced yawning in rats.
abstract: OBJECTIVE
  Curcumin is a major constituent of turmeric and influences many functions of the brain. In the present study, we investigated the effect of curcumin on yawning induced by apomorphine in rats.
  
  
  METHODS
  Curcumin administered orally for 10 consecutive days. Yawning was induced by subcutaneous (s.c.) injection of apomorphine (a dopamine receptor agonist) and the number of yawns was recorded for a period of 30 min.
  
  
  RESULTS
  Apomorphine (0.05 and 0.1 mg/kg) produced yawning. Haloperidol (a dopamine receptors antagonist) at a dose of 0.05 mg/kg partially and at a dose of 0.2 mg/kg completely inhibited apomorphine-induced yawning. Curcumin alone produced no yawning, whereas at doses of 30 and 60 mg/kg, it increased yawning induced by 0.1 mg/kg of apomorphine. Curcumin at the high doses (30 and 60 mg/kg) produced yawning when apomorphine (0.1 mg/kg) action was partially blocked with 0.5 mg/kg of haloperidol. In the presence of complete blockade of apomorphine (0.1 mg/kg) action with 0.2 mg/kg of haloperidol, curcumin did not produce yawning.
  
  
  CONCLUSIONS
  The results showed that curcumin at high doses increased apomorphine-induced yawning. In the presence of partial, but not complete blockade of apomorphine action, curcumin produced yawning. Curcumin produced a dopamine-like effect on yawning.
authors: Department of Basic Sciences, Faculty of Veterinary Medicine, Urmia University, Urmia 57153-1177, I.R. Iran.
authors: Esmaeal
authors: E
authors: Tamaddonfard
keywords: Apomorphine; Curcumin; Haloperidol; Rats; Yawning