Violeta Bucinskaite

It has been proposed that the vagus nerve plays a role in mediating cholecystokinin‐8 (CCK‐8) effect on such gastric functions as motility, emptying and gastric acid secretion. To examine the contribution of the efferent pathways in realizing these effects, efferent mass activity in the ventral gastric vagal nerve in Sprague‐Dawley rats was recorded. Intravenous infusion of CCK‐8 (0.1–1 nmol) suppressed the efferent activity. The effect of CCK‐8 was significantly reduced in animals with total subdiaphragmatic vagotomy in comparison to those with partial vagotomy. Intravenous infusion of CCK_A receptor antagonist L‐364,718 (1–100×10⁻⁶ g) blocked the response of vagal efferent activity to 0.1 nmol CCK‐8, but the CCK_B receptor antagonist L‐365,260 (1–100×10⁻⁶ g) did not in the conditions of either partial or total vagotomy. Intracisternal infusion of L‐364,718 (1×10⁻⁶ g) blocked the response of vagal efferent activity to 0.1 nmol CCK‐8 i.v. Infusion of exogenous CCK‐8 did not affect the activity of supradiaphragmatic vagal afferents. The results suggest that the effect of systemically administered CCK‐8 on vagal efferent activity is mediated by both peripherally (subdiaphragmatically) and centrally localized CCK_A receptors. British Journal of Pharmacology (2000) 129, 1649–1654; doi:10.1038/sj.bjp.0703270

The effects of treatment with sensory stimulation (electroacupuncture) or physical exercise (running) on heart rate, blood pressure and nociceptive thresholds in spontaneously hypertensive rats were studied. Both electroacupuncture and running increased blood pressure and heart rate when measured immediately after the experiment. Two hours later and at 8 and 16 h the heart rate values did not differ from the controls, while blood pressure was significantly decreased but returned to control level 16 h later. The experimental procedure significantly increased the nociceptive threshold which remained higher two hours later but did not differ from the controls after 8 and 16 hours. Concentrations of neuropeptide Y and calcitonin gene-related peptide in cerebrospinal fluid, plasma and muscle perfusate were measured immediately and 2, 8 and 16 h after the treatment. Increased levels of calcitonin gene-related peptide-like immunoreactivity and biphasical changes of neuropeptide Y-like immunoreactivity were found in all tissues analysed after electroacupuncture and running. The finding of similar changes in neuropeptides, blood pressure and nociception following electroacupuncture and running gives support to the hypothesis that sensory stimulation may stimulate endogenous control systems similarly as physical exercise.