ABSTRACT
Changes on levels gastric acidity, on serum gastrin, cAMP and cGMP levels were studied in 18 healthy volunteers after either stimulation (injection of 0.2 IU of soluble insulin/kg body weight to a group of 9 subjects) or stimulation and inhibition (injection of insulin plus atropine per os to the other group of 9 subjects) of the vagus nerve. After vagus nerve stimulation, gastric acid levels, serum gastrin and cGMP were raised and cAMP reduced. After stimulation and inhibition of vagus nerve, gastrin and cAMP were increased, cGMP reduced and gastric acid levels remained unchanged. These findings suggest that the vagus nerve, and more particularly the acetylcholine released from its metaganglionic fibers, stimulate parietal cells provoking acid secretion, and also stimulate G cells with subsequent gastrin secretion through cGMP.
Subject(s)
Gastric Acid/metabolism , Gastrins/metabolism , Nucleotides, Cyclic/metabolism , Vagus Nerve/physiology , Acetylcholine/physiology , Adult , Atropine/pharmacology , Blood Glucose/analysis , Cyclic AMP/blood , Cyclic GMP/blood , Female , Gastric Mucosa/cytology , Gastrins/blood , Humans , Insulin/pharmacology , Male , Parietal Cells, Gastric/metabolism , Vagus Nerve/drug effectsABSTRACT
Experiments carried on Albino rabbits for detecting cyclic GMP in the eye tissues and to observe whether cGMP is influenced through local administration of insulin to the eye, externally. Whereas, for instance, intraveinous administration of insulin does not influence, in any way, concentration of cGMP -- after 3' to 10' -- in the humour aqueous, the lens, the vitreous body and the blood serum, following administration of insulin by means of retrobulbar injection, for the same time and on the same tissues, the values of cGMP appear increased. On the other hand, results yielded by our experiments allow us to estimate that environment preparing cGMP in the eye is the retina and the choroid.