정상동물의 심근내 Catecholamines 분포에 관한 연구

Abstract

[한글]

[영문]

Accumulated evidence indicates that the catecholamines are stored as granule

within the celles of adrenal medulla or sympathetic nervous tissues. Myocardial

catecholmines have been shown to be present in the particulate fraction as well as

in the soluble fraction obtained by differential centrifugation of cell free

suspension from homogenates of cardiac muscle (Potter and Axelrod, 1962; Wegman and

Kako, 1962; Campos Shideman, 1962). Howere, according to these investigatore the

ratio to that in the soluble fraction of myocardium varies considerably. This may

be attributed to a species and fraction procedure difference.

Present experiment was designed to determine the intracellular distribution of

myocardial catecholamines, with special reference to the animal species.

The heart was rapidly removed from animals under ether anesthesia and 5 volumes

of 0.38 M ice-cold sucose in a waring blender. The resultant suspension was passed

through a double layer of gauze to remove the fibrous tissue. The homogenate was

then centrifuged at 3-5℃ for 10 minutes at 600 xg (low-speed centrifugation),

which brought down incompletely fragmented cells and nucli. A low-speed supernatant

was thus obtained, and was again centrifuged at 3-5℃ for 30 minutes at 15,000 xg

(high-speed centrifugation), which fractionated into supernatant and sediment. The

concentration of catecholamines in each fraction obtained by the above differential

centrifugation, was determined spectrophotofluormetrically by the modified

procedure of the method described by Shore and Olin (1958).

1. Examination of the intracellular distribution of the myocardial catecholamines

of normal rabbits showed that a higher concentration of the aminos was present in

the high-speed supernatant fraction (0.40ug/gm) and the ratio of

supernatant/sediment was 4. The catecholamines present in the low-speed supernatant

was almost completely recovered in both fractions obtained by high-speed

centrifugation.

2. In the cardiac homogenate of normal cats, a similar intracellular distribution

of catecholamines was observed. Thus, the concentrations of amines in high-speed

supernatant and sediment were 0.48 and 0.09ug/gm respectively.

3.In the experiment with cardiac homogenate of normal rate, it was also found

that higher concentration of catecholamines was present in the high-speed

supernatant and the ratio of supernatant/sediment was 4.3 which was not

significantly different from those observed in the cardiac homogenates of normal

rabbits or cats.

The concentrations of catecholamines in the high-speed supernatant and sediment

fractions would not represent the actual distribution in vivo. However, these

values are reproducible and relatively constant under the described experimental

conditions. Therefore, these may be considered useful as a criteria for the study

of intracellular distribution of myocardial catecholamines. From the above results,

it may be concluded that there is no significant difference in the intracellular

distribution of myocardial catecholamines of normal rabbits, cats and rats.