No abstract

Intraperitoneal injection of Semax (synthetic analogue of ACTH4-7, MEHFPGP) in a dose of 50 mg/kg produced a protective effect on rats with experimental indomethacin-induced ulcers. Experiments on narcotized rats showed that Semax in the studied dose had no effect on basal blood flow in the stomach, but prevented reduction of blood flow induced by indomethacin. The antiulcer effect of Semax is probably related to improvement of blood flow in the gastric wall disturbed by indomethacin.

Amylin (10(-10)M) induced relaxation of norepinephrine-precontracted rat aortic rings by more than 50%. This effect was preserved after blockade of NO-synthase and even after denudation of the vessel. Thus amylin-induced vasodilation is an endothelium-independent process not mediated by NO.

Changes in the heart rate were studied during stimulation of the effector nuclei of the vagus nerves--the dorsal vagal nucleus and the nucleus ambiguus--in anesthetized and unanesthetized cats. If groups of neurons, stimulation of which in anesthetized cats causes slowing of the heart, were stimulated in unanesthetized cats under conditions of free behavior, the heart rate was increased. Pharmacological beta-adrenergic receptor blockade by injection of Obsidan or Inderal (propranolol) demonstrated the parasympathetic nature of these effects. The fact that they are parasympathetic in nature was also confirmed by the character of the response: its short latent period and rapid disappearance of the effect after removal of the stimulation.