Fig. 1.

A: photomicrographs to show immunoreactivity for 5-HT (a; left, red) and phosphorylated CaMKII (b; right, green) in sections of duodenum following oral gavage of water (vehicle) (i) in prediabetic (PD) rats or glucose in PD (ii), recently diabetic (RD; iii), or 3 mo diabetic (3MD; iv) rats. In PD rats, orogastric gavage of glucose induced a significant increase in pCaMKII immunoreactivity compared with administration of water as indicated by numerous pCaMKII-labeled cells (ib vs. iib). The level of immunoreactive pCaMKII in enterochromaffine cells (ECs) following administration of glucose in RD and 3MD rats is much reduced compared with PD rats (iib vs. iiib and ivb). B: quantitative analysis of pCaMKII immunoreactivity in EC cells; pCaMKII in response to glucose gavage was significantly reduced in RD and 3MD rats compared with PD rats. C: quantitative analysis of 5-HT immunoreactivity in ECs from vehicle-treated PD, RD, and 3MD rats; there was a trend for a decrease in 5-HT immunoreactivity in the duodenum of 3MD rats compared with PD, but this did not reach statistical significance. Data are expressed as means ± SE, n = 3–5 rats per group, 48–67 cells/analyzed per treatment group. Significant differences between PD and RD or 3MD denoted by different letters; P < 0.001.