Unexpected insensitivity of the cholinergic motor responses to morphine in the human small intestine.
OBJECTIVE
morphine is known to inhibit cholinergic contractions of the guinea pig small intestine. This has been compared to the human small intestinal innervated longitudinal muscle in the current study.


METHODS
cholinergic primary contractions of human small intestinal longitudinal strips were evoked by electrical field stimulation (EFS; 0.5- 5 Hz in the presence of purinergic and nitrergic blockers or 5 Hz without pretreatment) and recorded isotonically in organ bath experiments. Guinea pig small intestinal segments were also studied.


CONCLUSIONS
neurogenic cholinergic contractions of human preparations were unaffected by morphine (1, 2 or 10 micromol/l). Longitudinal contractions of the guinea pig ileum were concentration-dependently suppressed by morphine (0.1-10 micromol/l). It is concluded that myenteric neurons supplying the longitudinal muscle of the human small intestine are much less sensitive to morphine than those of the guinea pig.
Benko
Rita
R
Department of Pharmacology and Pharmacotherapy, University Medical School of Pécs, Hungary.
Molnár
Zsuzsanna
Z
Nemes
Dániel
D
Dékány
András
A
Kelemen
Dezsö
D
Illényi
Lászlo
L
Cseke
Lászlo
L
Papp
András
A
Varga
Gábor
G
Bartho
Loránd
L
D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D004558:Electric Stimulation; D006168:Guinea Pigs; D006801:Humans; D066298:In Vitro Techniques; D007421:Intestine, Small / Q000187:drug effects* / Q000294:innervation; D009020:Morphine / Q000494:pharmacology*; D009119:Muscle Contraction / Q000187:drug effects*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D011950:Receptors, Cholinergic / Q000378:metabolism*
D000701:Analgesics, Opioid; D011950:Receptors, Cholinergic; D009020:Morphine