ABSTRACT
A biphasic pattern of collagen biosynthesis was found in the aortae of spontaneously hypertensive (SHR) rats; the time course of the rate of biosynthesis is similar to that described in the heart by Sen and Bumpus. In comparison to age-matched controls, collagen biosynthesis is elevated in the SHR rats, diminishes during the first fourteen weeks and rises again at the stage of established hypertension. In the period of established hypertension, the increased rate of collagen biosynthesis was associated with a pronounced rise of the collagen type I to type III ratio. On the other hand, in the pre-hypertensive stage, the proportion of collagen type III clearly exceeds the proportion of collagen type I in SHR rats.
Subject(s)
Aorta/metabolism , Collagen/metabolism , Hypertension/metabolism , Animals , Aorta, Abdominal/metabolism , Aorta, Thoracic/metabolism , Collagen/biosynthesis , Collagen/classification , Male , Rats , Rats, Inbred SHR , Rats, Inbred WKY , Time FactorsABSTRACT
The biosynthesis of collagen and elastin was followed during the development of spontaneous hypertension in rats (SHR) of the Okamoto-Aoki strain. Strain-matched animals of the same age, which did not develop hypertension, served as controls. Both collagen and elastin synthesis (as revealed by specific hydroxyproline activity) was found to exceed control levels in the prehypertensive period, to decrease during the development of hypertension and to increase again in the period of the established hypertensive state. From the two main collagen types present, synthesis of collagen type III exceeded that of type I in the prehypertensive period (at the age of 4 weeks) and this relation was reversed during the period of established hypertension. It is suggested that (a) the vascular connective tissue metabolism in SHR differs from that in strain-matched controls, and (b) the reverse rate of collagen type III to collagen type I synthesis during hypertension development may be considered an adaptive response to the increasing pressure load which may alter the mechanical properties of the vessel wall.
Subject(s)
Aorta/metabolism , Collagen/biosynthesis , Elastin/biosynthesis , Hypertension/metabolism , Rats, Inbred SHR/metabolism , Rats, Inbred Strains/metabolism , Animals , Blood Pressure , Male , RatsSubject(s)
Anti-Bacterial Agents/therapeutic use , Colchicine/therapeutic use , Collagen/antagonists & inhibitors , Connective Tissue/metabolism , Extracellular Matrix/metabolism , Proteins/antagonists & inhibitors , Arteries , Arteriosclerosis/drug therapy , Arteriosclerosis/metabolism , Collagen/metabolism , Humans , Male , Prostatic Hyperplasia/drug therapy , Prostatic Hyperplasia/metabolism , Proteins/metabolism , Pulmonary Fibrosis/drug therapy , Pulmonary Fibrosis/metabolism , Vascular Diseases/drug therapy , Vascular Diseases/metabolismSubject(s)
Cytoskeleton/metabolism , Golgi Apparatus/metabolism , Muscle, Smooth, Vascular/metabolism , Arteries/cytology , Arteriosclerosis/metabolism , Cytoskeleton/ultrastructure , Fibrin/biosynthesis , Golgi Apparatus/physiology , Golgi Apparatus/ultrastructure , Humans , Hypertension/metabolism , Microtubule-Associated Proteins/physiology , Muscle, Smooth, Vascular/cytology , Muscle, Smooth, Vascular/ultrastructureABSTRACT
Colchicine treatment resulted in the appearance and proliferation of smooth sarcoplasmic reticulum in some smooth muscle cells of the aortic and pulmonary trunk walls in the rabbit. The significance of cytoplasmic microtubules and/or membrane-bound tubulin for the morphogenesis, functioning and control of smooth endoplasmic reticulum in different kinds of cells is discussed.
Subject(s)
Colchicine/pharmacology , Muscle, Smooth, Vascular/ultrastructure , Sarcoplasmic Reticulum/ultrastructure , Animals , Aorta , Cytoskeleton/physiology , Endoplasmic Reticulum/physiology , Endoplasmic Reticulum/ultrastructure , Microscopy, Electron , Microtubules/physiology , Muscle, Smooth, Vascular/drug effects , Rabbits , Tubulin/physiologyABSTRACT
Smooth membrane-limited vesicles and cisternae are closely associated with spindle microtubules in mitotic pulmonary trunk smooth muscle cells of the rabbit. This may play a regulatory role in the structure-function integrity of the spindle.
Subject(s)
Microtubules/ultrastructure , Muscle, Smooth, Vascular/ultrastructure , Animals , Microscopy, Electron , Mitosis , Rabbits , Sarcoplasmic Reticulum/ultrastructureABSTRACT
A highly developed vacuolar apparatus is found in aorta and pulmonary trunk smooth muscle cells and elastic cartilage chondrocytes, and its relationship with cytoplasmic microtubules is described. The Golgi complex as well as the rough endoplasmic reticulum (RER) may be the intracellular sources of the components of the vacuolar apparatus. Some vacuoles, Golgi-related only, showed an association with microtubules. Smooth muscle cells which contained vacuoles derived from RER did not possess Golgi vacuoles and microtubules. In chondrocytes, both Golgi-related and RER vacuoles coexisted in a single cell. 2 main secretory pathways are suggested to operate in smooth muscle cells and chondrocytes: Golgi and RER pathway. The former requires an intact cell tubulin system (cytoplasmic microtubules and membrane-bound tubulin), while the latter is probably microtubule-independent.
