BACKGROUND Vascular smooth muscle cell proliferation is the key event of coronary artery disease. Mechanical forces, in particular, pulsatile stretch and platelet-derived growth factor, may play an important role. METHODS AND RESULTS Vascular smooth muscle cells were cultured from the media of human left descending coronary arteries obtained from organ donors using the explant method. To stud...

Applying a small stretch to active muscle immediately before shortening results in an increase in force and work done during subsequent shortening. The basis of the increase is not fully understood, having important implications for work and efficiency, and how they are influenced through stretch. We used the anterior tibialis muscle of leopard frogs (Rana pipiens complex) to measure the oxygen...

BURNSTOCK, GEOFFREY AND C. L. PROSSER. Responses of smooth muscles to quick stretch; relation of stretch to conduction. Am. J. Physiol. rg8(5) : g21--93:s. I g6o.-Quick stretches applied to isolated strips of visceral muscles elicit contractions and electrical responses, similar stretches elicit no responses from blood vessels and nictitating membrane. Highly excitable muscles gave repetitive r...

The activity of hindlimb motor units from the lateral gastrocnemius and tibialis anterior muscles in the awake rat was compared during locomotion and during slow, sinusoidal muscle stretch. The majority of units were activated with high initial frequencies and often commenced firing with an initial doublet or triplet, even when activated by slow muscle stretch. The high firing rates at recruitm...

Although the muscle mechanoreflex is one of the pressor reflexes during exercise, its interaction with dynamic characteristics of the arterial baroreflex remains to be quantitatively analyzed. In anesthetized, vagotomized, and aortic-denervated rabbits (n = 7), we randomly perturbed isolated carotid sinus pressure (CSP) using binary white noise while recording renal sympathetic nerve activity (...

Skeletal muscle responds to passive overstretch through sarcomerogenesis, the creation and serial deposition of new sarcomere units. Sarcomerogenesis is critical to muscle function: It gradually re-positions the muscle back into its optimal operating regime. Animal models of immobilization, limb lengthening, and tendon transfer have provided significant insight into muscle adaptation in vivo. Y...

Sensitivity differences between primary and secondary endings of mammalian muscle spindles under various conditions of stretch and fusimotor activation may be due to differences in their respective mechanoelectric transducers or to mechanical properties of the intrafusal muscle supporting those endings. This study of isolated cat muscle spindles examines the strain in individual intrafusal musc...

The relationship between segmental mobility and the organisation of thoracic stretch receptors was examined in the deep-sea isopod Bathynomus doederleini, which shows a developed adaptive behaviour during digging. The movements of segments during digging were analysed from video recordings, which showed that a large excursion occurred in the anterior thoracic segments. Dye-fills of axons reveal...

OBJECTIVE To develop a three-dimensional computer model to predict levator ani muscle stretch during vaginal birth. METHODS Serial magnetic resonance images from a healthy nulliparous 34-year-old woman, published anatomic data, and engineering graphics software were used to construct a structural model of the levator ani muscles along with related passive tissues. The model was used to quanti...

The measurement of ventricular diastolic compliance is complicated by the presence of viscous properties. To approach this problem, cat papillary muscles contracting isometrically at 15/min at 26 degrees C were stretched at different velocities during diastole. At a given length there was no excess of force above that defined by the static force-length curve until velocity of stretch exceeded 1...