Leptin excites enteric neurons of guinea-pig submucous and myenteric plexus

Abstract

Leptin activates submucous and myenteric neurons indicating relevance for adipocyte-ENS signaling. These results set the basis for further studies to reveal the functional correlate of the neural action of leptin in the ENS.

Leptin modulates enteric neurotransmission in the rat proximal colon: An in vitro study

“…For the present study, it was decided to use a concentration of leptin (0.1 μM = 0.395 μg•mL − 1) to characterize the mechanisms involved in leptin action on tone and TNS-induced relaxation even though this concentration has no effect on TNS-induced contraction. This concentration has previously been shown to activate anorexigenic proopiomelanocortin neurons in mice [38] and enteric neurons in guineapig [33] and to stimulate vagal afferents in cats [29].…”

“…If leptin is produced locally, for instance by adipocytes in colonic submucosa [33,37] its receptors may be desensitized, which might explain the weak but significant effect of exogenous leptin on enteric neurons. Indeed, our results were consistent with those from previous studies showing that leptin modulates GI tract motility [24], hyperpolarizes glucoresponsive enteric neurons [31] and excites enteric neurons of submucous and myenteric plexus [33]. For the present study, it was decided to use a concentration of leptin (0.1 μM = 0.395 μg•mL − 1) to characterize the mechanisms involved in leptin action on tone and TNS-induced relaxation even though this concentration has no effect on TNS-induced contraction.…”

“…Because leptin receptors have been found in the antral and intestinal ENS of rodents, the effects of leptin on gut motility and nutrient absorption might be due to modulation of ENS activities [31,32]. Thus, leptin was shown to hyperpolarize glucoresponsive enteric neurons in guinea-pig [31] and recently to activate colonic submucous and myenteric plexus [33]. However, the precise mechanisms involved are so far unknown.…”

The Enteric Nervous System

“…One of the fi rst studies to look at changes to the ENS that might accompany alterations in diet was Reichardt et al ( 2011 ) where the anorexigenic hormone leptin was examined. Leptin is released from adipocytes and supresses central appetite signalling and their hypothesis was that peripheral effects of leptin at the level of the ENS were present.…”

Excitability and Synaptic Transmission in the Enteric Nervous System: Does Diet Play a Role?

“…One of the first studies to look at changes to the ENS that might accompany alterations in diet was Reichardt et al (2011) where the anorexigenic hormone leptin was examined. Leptin is released from adipocytes and supresses central appetite signalling and their hypothesis was that peripheral effects of leptin at the level of the ENS were present.…”