심룡근(心朧筋)의 반복수축현상(反復收縮現象)에 관(關)하여

• 영문명: After Contraction in Isolated Cardiac Muscle
• 발행기관: 대한생리학회
• 저자명: 여웅연(Ryo, Ung-Yun) Brooks, Chandler Mcc.
• 간행물 정보: 『대한생리학회지』제1권 제1호, 67~72쪽, 전체 6쪽
• 주제분류: 의약학 > 의학일반
• 파일형태: PDF
• 발행일자: 1967.06.30

영문 초록

Present paper is attempted to introduce the phenomenon of after contraction in isolated cardiac-muscle. Papillary muscles were removed from cat right ventricle and were used as a preparation. The muscle strip was Placed in tissue bath which is kept in steady temperature of around 25℃ and was perfuced by Tyrode solution, saturated with 95% O₂ and 5% CO₂. Under the condition of high calcium (8.2-10.0 mM/l), low sodium (72.4-70.0 mM/l) perfusion with the administration of epinephrine (1-2 mg/l) into tile tissue bath normally triggered muscle contraction was followed by oscillatory, repetitive contractions - after contraction. The phenomenon of after contraction was augumented by decrease in tissue bath temperature and by increase in number of preceding beats and in driving rate. Authors were able to maintain the phenomenon in prominent and steady state giving proper experimental conditions such as fixed bath temperature (ranged from 22℃ to 27℃), suitable driving rate (20 per minute in average) and perfusion of high calcium, loll sodium and 1-2 mg/l of epinephrine. In some preparations, the strength of after contraction (second contraction) reached up-to 80% of normally triggered contraction and five repetitive contractions were observed as largest number of after contractions. Intracellular action potential measured in the muscle which was beating regulary showing steady after contraction revealed no oscillating after potential in most parts of the muscle but in few cases oscillating changes of after potentials were detectable. In electrogram of the muscle preparation recorded by means of contact electrode prominent, oscillating after potentials were observable when the recorder was set at highest sensitivity. It still is not clear that whether after contraction is the phenomenon which corresponds to those changes in action potential, oscillating after potential, of the muscle preparation. Possible mechanism of the phenomenon of after contraction relating with after potential changes was proposed. Detailed results obtained from further studies on after contraction and concrete discussion on the phenomenon will be reported by authors.