Figure 1.

Accelerated gastric emptying and increased phasic responses to cholinergic stimulation in Lepr^db/db mice. (A–B) Time course (top) and half-times (T_1/2; bottom) of solid gastric emptying measured by [¹³C]-octanoic acid breath test in female Lepr^db/db and WT mice (n=5–7/genotype). Note rapid emptying in the Lepr^db/db animals. (B) Characteristics of electrical slow waves and spike potentials recorded from circular smooth muscle cells of Lepr^db/db mice (70 cells, 6 animals) and WT mice (62 cells, 5 animals). Note modest gains in slow wave and spike amplitudes and rates-of-rise, and in spike frequency in Lepr^db/db tissues. (C–D) Electrical (C; n=4/genotype) and contractile responses (D; n=4–6/genotype) to the cholinergic agonist carbachol (CCh; 100 nM). Slow waves were recorded in the presence of the L-type Ca²⁺ channel blocker nicardipine (1 μM following pretreatment with 2 μM). Spikes were incompletely inhibited by nicardipine but were not analyzed. Small (<0.5-mN), irregular contractile events were also not analyzed. CCh elicited greater increases in slow wave and contractile frequencies and peak contractile force in Lepr^db/db tissues.