Moderate Elevation of Extracellular K⁢ Concentration Induces Vasorelaxation in Isolated Rat, Rabbit and Human Cerebral Arteries Role of Na Pump and Ba-Sensitive Process

• 영문명: Moderate Elevation of Extracellular K^⁢ Concentration Induces Vasorelaxation in Isolated Rat, Rabbit and Human Cerebral Arteries Role of Na Pump and Ba-Sensitive Process
• 발행기관: 대한생리학회-대한약리학회
• 저자명: Dong Ho Kim Sung Joon Kim Sang Jin Lee Sung Jin Park Ki Whan Kim
• 간행물 정보: 『The Korean Journal of Physiology & Pharmacology』제2권 제6호, 705~714쪽, 전체 10쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 1998.01.01

영문 초록

Cerebral blood vessels relax when extracellular K^⁢ concentrations ([K^⁢])_e are elevated moderately (2∼15 mM, K^⁢-induced vasorelaxation). We have therefore studied the underlying mechanism for this K^⁢- induced vasorelaxation in the isolated middle cerebral arteries (MCAs). The effects of ouabain and Ba^2⁢ on K^⁢-induced vasorelaxation were examined to determine the role of sodium pump and/or Ba-sensitive process (possibly, inward rectifier K current) in the mechanism. Mulvany myograph was used to study 24 rats, 18 rabbits, and 10 humans MCAs (216⁑3 ㄍm, 347⁑7 ㄍm, and 597⁑39 ㄍm in diameter when stretched to a tension equivalent to 55 mmHg). High K^⁢ (125 mM) and PGF_2α (1∼10 ㄍM) induced concentration-dependent contractions in all 3 species, while histamine (10∼50 ㄍM) evoked contraction only in the rabbits and induced relaxation in the rats and humans. Addition of K^⁢ (2∼10 mM) to the control solution induced vasorelaxations. These effects were inhibited by the pretreatment with both ouabain (10 ㄍM) and Ba^2⁢ (0.1∼0.3 mM) in the rat, but only with ouabain (10 ㄍM) in the rabbit and human. These results suggest that K^⁢-induced vasorelaxation occurs via the stimulation of electrogenic Na pump in the rabbit and human MCAs, while in the rat MCAs via the activation of both Na pump and Ba-sensitive process.

키워드

Cerebral artery Vasorelaxation Myograph Potassium Ouabain Barium