Effects of stimulation and damage of afferent nerves on the glucose and free fatty acid levels in the rat blood under various glycemic conditions

Capsaicin stimulation of afferent neurones increased hyperglycaemic responses to glucose and decreased hypoglycaemia in control rats. Elevation of the free fatty acids level occurred following both the stimulation alone and that combined with insulin. Neonatal capsaicin pre-treatment decreased the hypoglycaemic response effect of insulin and the FFA level. Treatment of adult rats with capsaicin did not affect hypoglycaemia following insulin administration but did decrease the FFA level. In capsaicin pre-treated rats, the capsaicin stimulation exerted no effect upon the hypoglycaemia following insulin administration but abolished the insulin effect on the FFA level. The findings suggest that the capsaicin-sensitive nerves play a major role in mediating the glucose and the FFA metabolic responses.