[Role of vagal intestinal glucoreceptors in insulin regulation]

This paper summarizes recent data on the existence of insulin nervous regulation by duodenal glucoreceptors which are connected to non-medullated fibres included in the vagal nerves. These glucoreceptors respond to intestinal perfusion of glucose or other carbohydrates, but other conventional mechanical stimuli are unable to activate them; therefore, they must be considered as true specific glucoreceptors. Their activation produces an immediate increase of insulin which precedes changes in glycemia. From bivagotomy experiments and from experiments which pharmacologically exclude the efferent parasympathetic or sympathetic fibres, it has been shown that this regulation is chiefly mediated by the vagal nerves. On the other hand, it was found that glucoreceptor afferents project on the hypothalamic nuclei (VMH and LHA) like the whole splanchnic and vagal afferents. The physiological importance and the role of insulin nervous regulation are discussed.