흰쥐 심근의 역 사다리 효과에 있어서 생후 연령에 따른 Na+-Ca2+ 교환의 역할에 관한 연구

• 영문명: Studies on the Roles of Na+-Ca2+ Exchange according to Postnatal Age in the Negative Staircase Effect of the Rat Heart
• 발행기관: 대한생리학회-대한약리학회
• 저자명: 이해용(Hae yong Lee) 김순진(Soon Jin Kim)고창만(Chang Mann Ko)
• 간행물 정보: 『The Korean Journal of Physiology & Pharmacology』제1권 제6호, 707~716쪽, 전체 10쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 1997.01.01

영문 초록

Recent reports revealed that the Na^⁢-Ca^2⁢ exchangers and feet structures of sarcoplasmic reticulum(SR) are located in close vicinity in the specific compartment. Therefore, we investigated the possibility that the Na^⁢-Ca^2⁢ exchanger may decrease the tension development by transporting the Ca^2⁢ out of the cell right after it released from SR, on the basis of this anatomical proximity. We exammined the negative force-frequency relationship of the developed tension in the electrically field stimulated left atria of postnatal developing rat(1, 3 day, 1 week and 4 week old after birth). Cyclopiazonic acid(3x10^-5 M) treatment decreased the developed tension further according to postnatal age. Monensin(3x10^-6 M) treatment did not increase the maximal tension in 4 week-old rat, preserving negative staircase, while the negative staircase in the younger rat were flattened. Ca^2⁢ depletion in the buffer elicited more suppression of the maximal tension according to the frequency in all groups except the 4 week-old group. The % decrease of the maximal developed tension of 4 week-old group at 1 Hz to that of 0.1 Hz after Na^⁢ and Ca^2⁢ depletion was only a half of those of the yonger groups. Taken together, it is concluded that the Na^⁢-Ca^2⁢ exchange transports more Ca^2⁢ released from SR out of the cell in proportion to the frequency, and this is responsible for the negative staircase effect of the rat heart.

키워드

Postnatal developing heart Rat Na^⁢ -Ca^2⁢ exchange Monensin sarcoplasmic reticulum Negative staircase effect