Little is known about the acute and chroniceffects of the intestinal transplantation on smoothmuscle contractile physiology. Our aim was to determinethe effects of the denervation necessitated byjejunoileal autotransplantation on membrane potential andcontractile activity. Six dogs underwent a model ofjejunoileal autotransplantation that specifically avoidsischemia/reperfusion injury (by maintaining blood flow to the gut during the“transplantation” procedure). Strips ofjejunal circular muscle were studied sequentially beforeand 2 and 8 weeks after denervation by recordingmechanical and intracellular electrical activities in vitro. The amplitudeof spontaneous contractions ( $${\bar X}$$ ± SD) was increased (P < 0.05) at 2 comparedto 0 weeks (126 ± 19 vs 77 ± 32 g/g; P< 0.05) but markedly decreased at 8 weeks (7 ±2 g/g). Contraction frequency, resting membranepotential, and amplitude of slow waves were unchangedacross these time points. Bethanechol (10-7-10-4 M) and substance P (10-8-10-6 M) dose-dependently increasedcontractile activity at all time points, but the absolutechange in amplitude was decreased at 8 weeks. Theamplitude of inhibitory junction potentials (IJPs) andduration of inhibition of contractile activity in the presence of cholinergic and adrenergic blockadeincreased at 2 and 8 weeks; off-contraction amplitudewas decreased at 8 weeks (P < 0.05). These effectsmay occur via changes in neurotransmitter release, changes in regulation of membrane receptors, oralteration of characteristics of the membrane thresholdpotential.