Stimulation of sympathetic innervation in the upper gastrointestinal tract as a treatment for obesity

Abstract

Sympathetic activity and obesity have a reciprocal relationship. Firstly, hypothalamic obesity is associated with decreased sympathetic activity. Caffeine and ephedrine increase sympathetic activity and induce weight loss, of which 25% is due to increased metabolic rate and 75% is due to a reciprocally decreased food intake. Secondly, hormones and drugs that affect body weight have an inverse relationship between food intake and metabolic rate. Neuropeptide Y decreases sympathetic activity and increases food intake and body weight. Thirdly, a gastric pacemaker Transcend and vagotomy increase the ratio of sympathetic to parasympathetic activation, decrease food intake, and block gut satiety hormones. Weight loss with the pacemaker or vagotomy is variable. Significant weight reduction is seen only in a small group of those treated. This suggests that activation of the sympathetic arm of the autonomic nervous system may be most important for weight loss. Systemic sympathetic activation causes weight loss in obese patients, but side effects limited its use. We hypothesize that selective local electrical sympathetic stimulation of the upper gastrointestinal tract may induce weight loss and offer a safer, yet effective, obesity treatment. Celiac ganglia delivers sympathetic innervation to the upper gastrointestinal tract. Voltage regulated electrical simulation of the rat celiac ganglia increased metabolic rate in a dose-dependent manner. Stimulation of 6, 3, or 1.5 V increased metabolic rate 15.6%, 6.2%, and 5%, respectively in a single rat. These responses support our hypothesis that selective sympathetic stimulation of the upper GI tract may treat obesity while avoiding side effects of systemic sympathetic activation.

Fig. 1

The first selective electrical stimulation (6 V, filled bar) of the celiac ganglia significantly increased metabolic rate compared to post-stimulation (open bar) (P < 0.001).

Fig. 2

The second stimulation of 1.5 V/30 cpa/100 ms followed by 3 V/30 cps/100 ms increased the metabolic in a voltage dependent manner.

Fig. 3

The percentage increase in metabolic rate to electrical stimulation with 1.5 V/30 cps/100 ms followed by 3 V/30 cps/100 ms was greater than non-simulation.