Sensitivity of Rabbit Cerebral Artery to Serotonin is Increased with the Moderate Increase of Extracellular K⁢

• 영문명: Sensitivity of Rabbit Cerebral Artery to Serotonin is Increased with the Moderate Increase of Extracellular K^⁢
• 발행기관: 대한생리학회-대한약리학회
• 저자명: Suk Hyo Suh Sung Jin Park Jai Young Choi Jae Hoon Sim Young Chul Kim Sung Joon Kim Insuk So Ki Whan
• 간행물 정보: 『The Korean Journal of Physiology & Pharmacology』제2권 제6호, 695~703쪽, 전체 9쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 1998.01.01

영문 초록

[K^⁢]_O can be increased under a variety of conditions including subarachnoid hemorrhage. The increase of [K^⁢]_O in the range of 5∼15 mM may affect tensions of blood vessels and can change their sensitivity to various vasoactive substances. Therefore, it was examined in the present study whether the sensitivity of cerebral arteries to vasoactive substances can be changed with the moderate increase of [K^⁢]_O, using Mulvany-type myograph and [Ca^2⁢]_c measurement. The contractions of basilar artery and branch of middle cerebral artery induced by histamine were not increased with the elevation of [K^⁢]_O from 6 mM to 9 mM or 12 mM. On the contrary, the contractions induced by serotonin were significantly increased with the elevation of [K^⁢]_O. The contractions were also significantly increased by the treatment with nitro-L-arginine (10^⁣4 M for 20 minutes). In the nitro-L-arginine treated arteries, the contractions induced by serotonin were significantly increased with the elevation of [K^⁢]_O from 6 mM to 12 mM. K^⁢-induced relaxation was evoked with the stepwise increment of extracellular K^⁢ from 0 or 2 mM to 12 mM by 2 mM in basilar arterial rings, which were contracted by histamine. But [K^⁢]_O elevation from 4 or 6 mM to 12 mM by the stepwise increment evoked no significant relaxation. Basal tension of basilar artery was increased with [K^⁢]_O elevation from 6 mM to 12 mM by 2 mM steps or by the treatment with ouabain and the increase of basal tension was blocked by verapamil. The cytosolic free Ca^2⁢ level was not increased by the single treatment with serotonin or with the elevation of [K^⁢]_O from 4 mM to 8 or 12 mM. In contrast to the single treatment, the Ca^2⁢ level was increased by the combined treatment with serotonin and the elevation of [K^⁢]_O. The increase of free Ca^2⁢ concentration was blocked by the treatment with verapamil. These data suggest that the sensitivity of cerebral artery to serotonin is increased with the moderate increase of [K^⁢]_O and the increased sensitivity to serotonin is due to the increased [Ca^2⁢]_i induced by extracellular Ca^2⁢ influx.

키워드

Rabbit cerebral artery Arterial sensitivity to serotonin Moderate elevation of [K^⁢ ]o