SARI Z, ZARRINDAST M, ROUSHANZAMIR F. MORPHINE AND APOMORPHINE INHIBIT GASTROINTESTINAL TRANSIT (GIT) THROUGH TWO DIFFERENT MECHANISMS. Med J Islam Repub Iran 1999; 13 (2) :133-138
URL:
http://mjiri.iums.ac.ir/article-1-957-en.html
From the Department of Physiology, Arak University of Medical Sciences, Arak
Abstract: (4017 Views)
Morphine was used as a remedy for the control of diarrhea centuries before it's
sedative-analgesic effect was discovered.
Although several mechanisms have been proposed for the morphine-induced
inhibition of gastrointestinal transit (OIT), the exact mechanism has not yet been
identified. On this basis the possible involvement of the dopaminergic system in
morphine-induced inhibition of transit was investigated.
This study showed that morphine decreased gastrointestinal transit (OIT) of
charcoal dust in mice.in a dose-dependent manner. The response was inhibited by
the opiate antagonist naloxone. Pretreatment of animals with the D-2 antagonist
sulpiride or the peripheral dopamine antagonist domperidone did not alter the
morphine-induced inhibition of OIT. The D-l/D-2 agonist apomorphine also
decreased OIT in mice. The response was inhibited by SCH 23390 or sulpiride
pretreatment (p<0.01), but not by domperidone or naloxone. It is concluded that
morphine and apomorphine inhibit OIT through opiate and dopaminergic
mechanisms, respectively.