Experimental Studies on the Vascular Smooth Muscle of $Cd^{2+}$-poisoned Rabbits

카드뮴중독(中毒) 가토(家兎)의 동정맥(動靜脈)에 관하여

The tension-length relationships and reactivity of vascular smooth muscle in longitudinal strips from portal vein ana in helical strips from thoracic aorta and pulmonary artery of normotensive control and cadmium-hypertensive rabbits were studied in vitro. 1. The mean arterial pressures of non-poisoned control rabbits was $87.0{\pm}4.7 mmHg$. However, Cd-poisoned group revealed the significant increase in pressure by $109.04{\pm}2.8 mmHg$ (p<0.005). 2. By tension-length studies, strips from portal vein of Cd-poisoned group stretched a greater percent increase in length in response to an applied resting force from 0.25 to 5 g than did those from non-poisoned group. On the contrary, strips from thoracic aorta of Cd-poisoned group showed less compliant than those from control, i.e. the former underwent a less percent increase in length than the latter. Passive tension-length relations of pulmonary artery was unaffected by Cd-hypertension. 3. The force of contraction(active tension) was significantly lowered in strips from aorta of Cd-hypertensive group throughout the range of $0.5{\sim}2g$ passive tension. However, there was no significant difference in the development of active tension of portal vein or pulmonary artery of both groups. 4. The $K^+$-contraction in the portal vein, aorta and pulmonary artery of Cd-poisoned group made no difference in the active force from those of control group. 5. The force of contraction in the strips from aorta of Cd-poisoned group was significanty decreased compared to that of control. The results suggested that the alterations in vascular reactivity to contracting substances and in distensibility to passive tension were induced in the Cd-hypertensive rabbits.

Cd 중독(中毒)으로 가토(家兎)에 고혈압(高血壓)을 일으키고 이를 중독(中毒) 가토(家兎)와 대조(對照) 비중독(非中毒) 가토(家兎)의 간문맥(肝門脈), 흉부(胸部) 대정맥(大動脈) 및 폐정맥(肺動脈)을 적출하여 in vitro에서 장력(張力)-길이의 관계를 관찰하고 NE, $K^+$-depolariration 및 angiotensin의 수축(收縮) 효과(效果)를 비교(比較)하였다. 1. 비중독(非中毒) 대조군의 평균 동맥압은 $87.0{\pm}4.7mmHg$이었고 Cd 중독군(中毒群)에서는 $109.0{\pm}2.8mmHg$로 Cd 중독(中毒)에 의하여 의의(意義)있는 증가(增加)를 나타내었다. 2. 동(動) 정맥(靜脈)의 장력(張力)-길이 곡선(曲線)에서 Cd 중독(中毒) 가토의 간문맥(肝門脈)은 passive tension의 증가에 따라 distensibility가 현저히 증가되나 대동맥(大動脈)에 있어서는 오히려 대조군에 비(比)하여 유의(有意)한 감소(減少)를 나타내었고 폐동맥(肺動脈)은 아무런 차이(差異)를 나타내지 아니하였다. 3. Passive tension의 증가에 따른 active tension의 변화(變化)는 대동맥(大動脈)에 있어서는 Cd중독으로 현저히 감약되었으나 간문맥(肝門脈)이나 폐동맥(肺動脈)은 대조군과 별다른 차이(差異)가 없었다. 4. Cd 중독군(中毒群)이나 비중독(非中毒) 대조군에서 passive tension의 변동에 따른 수축결과(收縮效果)는 세 혈관에서 모두 유의(有意)한 차이를 나타내지 아니하였다. 5. 대동맥(大動脈) 절편에 대한 angiotensin의 수축(收縮) 효과(效果)는 Cd 중독군(中毒群)에서 유의하게 저하되었다.