Related Experiment Videos
Developmental changes in morphine and clonidine sensitivity of isolated chick oesophagus
1Department of Pharmacology, Faculty of Medicine, Tehran University of Medical Sciences, Iran.
General Pharmacology
|July 1, 1992
Abstract:
1. Electrically evoked contractions of isolated newly-hatched and over 6 week-old chicks cervical oesophagus (pre-crop) were inhibited by morphine and clonidine in a dose-dependent manner. 2. The inhibitory effects of morphine and clonidine were antagonized by naloxone (3 x 10(-6) M) and yohimbine (10(-7) M), respectively. 3. IC50 for morphine was 1.01 x 10(-7) M for newly-hatched and 5.19 x 10(-6) M for adult chicks. 4. IC50 for clonidine was 2.34 x 10(-9) M for newly-hatched and 1.19 x 10(-8) M for adult chicks. 5. These findings indicate a significant decrease in inhibitory effect of morphine and clonidine during developmental stages.