An Equipment Used for Studying the Vestibular Perception of Gekko gecko

The study of vestibule neurons specific firing mode of Gekko gecko under stimulus of different angles and rotating speeds has an important theoretical significance to reveal the control mechanism of Gekko geckos vestibular position as well as to the development of gecko-robots. A vari-angle rotating equipment was made to give different stimulus in study of Gekko geckos vestibular electrophysiology. The equipment mainly consisted of four parts as follows: fastening panel for stereotaxic instrument, shaft locking device, counterweight, driving system. The shaft locking device and counterweight realized tight fixation and torque equilibrium at different angles respectively. Fastening panel matched the general stereotaxic instrument. A stepper motor driver controlled the velocity and acceleration of rotation. Initial experiment verified that the equipment had superiority of easy operation, reliable positioning and accurate control of angle and speed, which indicated that it could meet the demand of the Gekko geckos vestibule research.

Glucagon-like peptide (GLP-1) is involved in the central modulation of fecal output in rats

In addition to its insulinotropic action, exogenously administered glucagon-like peptide (GLP-1) inhibits gastropancreatic motility and secretion via central pathways. The aims of the present study were to evaluate the effects of exogenous GLP-1-(7–36) amide on fecal output and to investigate the role of endogenous GLP-1 on stress-induced colonic activity. With the use of a stereotaxic instrument, adult male Sprague-Dawley rats weighing 200–250 g were fitted with stainless steel cerebroventricular guide cannulas under ketamine anesthesia. A group of rats were placed in Bollman-type cages to induce restraint stress. Fecal output monitored for 2 h was increased significantly by intracerebroventricular GLP-1 to 500, 1,000, and 3,000 pmol/rat ( P < 0.05–0.01), whereas intraperitoneal GLP-1 had no effect. Intracerebroventricular administration of the GLP-1 receptor antagonist exendin-(9–39) (10 nmol/rat) reversed the increases induced by GLP-1 (500 pmol/rat; P < 0.01). Similar results were also observed with the injection of corticotropin-releasing factor receptor antagonist astressin (10 μg/rat icv). The significant increase in fecal pellet output induced by restraint stress was also decreased by both intracerebroventricular exendin (10 nmol/rat) and astressin (10 μg/rat; P < 0.01–0.001). These results suggest that GLP-1 participates in the central, but not peripheral, regulation of colonic motility via its own receptor and that GLP-1 is likely to be a candidate brain-gut peptide that acts as a physiological modulator of stress-induced colonic motility.