Effect of transient receptor potential channel m4 on cerebral artery myogenic tone following subarachnoid hemorrhage in rats / 中国脑血管病杂志

ABSTRACT

Objective: To investigate the effect of transient receptor potential channel M4 (TRPM4) on cerebral artery myogenic tone following subarachnoid hemorrhage (SAH) in rats. Methods: Sixty cleangrade healthy SD rats of both sexes were randomly divided into SAH group (n = 30) and sham operation group (n =30) according to the random number table. A SAH model was induced by injecting autologous rat tail artery blood into the suprasellar cistern of rats with stereotactic apparatus. 0.2 ml autologous arterial blood was injected into the rats of the SAH group and 0.2 ml isotonic saline was injected into the rats of the sham operation group. Five days after inducing the SAH model,the cerebral arteries of rats were separated, and the diameter of cerebral arteries was observed by the pressurized myography, and the myogenic tone was calculated. The cerebral arteries of each experimental group were observed by time-sequence method for artificial cerebrospinal fluid(aCSF), containing 0. 03 mmol/L TRPM4 specific blocker 9-phenanthrol (9- Phe) aCSF and containing 0. 1 mmol/L diltiazem in the calcium-free aCSF in the arterial diameters, and according to this, the myogenic tone was calculated. Results: After SAH, when the cerebral artery was located in aCSF,the cerebral artery diameter of the SAH group was significantly smaller than that of the sham operation group (45.9 ±6. 6 u.m vs. 74. 9 ±5. 1 u,m,i = 5. 08,P <0. 05). Cerebral artery myogenic tone was significantly higher than that of the sham operation group (58. 7 ±2. 4% vs. 41. 2 ±3. 4%;t - 2.11,P < 0. 05). After adding 9-Phe to aCSF, the diastole of cerebral artery diameters of the SAH group and sham operation group was more obvious than that before adding (98. 4 ± 6. 1 and 95. 1 ±5.5 u,m, respectively). The difference was statistically significant (both P<0.05). The decreased myogenic tone in the SAH group was significantly higher than that in the sham operation group (42. 4 ±4. 4% vs. 15. 3 ± 3. 2%;t =2. 83,P < 0. 05). Conclusion: After SAH,TRPM4 mediates the increased myogenic lone of cerebral artery in rats.