AIMS To clarify factor(s) involved in morphological dedifferentiation of retinal pigment epithelial (RPE) cells in vitro from mitotically quiescent hexagonal cells to flattened cells that lack epithelial characteristics and concurrent myoid differentiation. METHODS RPE cells which retained their differentiated hexagonal morphology were isolated from bovine eyes by mechanical pipetting. Dediff...

The present study was designed to investigate the effects of alpha and beta adrenergic receptor blockers on caffeine-induced increase in canine hindlimb glucose uptake. The study was carried out on fasted male anaesthetized dogs divided into five groups [5 dogs per group]. Each dog was given a bolus injection of normal saline, caffeine [6 mg/kg] caffeine after pretreatment with prazosin [0.2 mg...

Passage of spermatozoa through the epididymis and emission of sperm during ejaculation are based on spontaneous and induced contractions of epididymal peritubular muscle layers. This study deals with the ejaculation-relevant factors noradrenaline (NA) and oxytocin (OT) and their contractile effects in the course of the bovine epididymal duct. Muscle tension recording revealed excitatory effects...

The time course of the effects of phenylephrine (10 mumol/l) on force of contraction and on inositol phosphates in electrically driven left auricles from rat hearts labeled with [3H]inositol was studied. All experiments were performed in the presence of propranolol (1 mumol/l) and LiCl (10 mmol/l). Products measured after separation with high-performance liquid chromatography were inositol 1-ph...

Evidence is accumulating to suggest that actin filament remodeling is critical for smooth muscle contraction, which implicates actin filament ends as important sites for regulation of contraction. Tropomodulin (Tmod) and smooth muscle leiomodin (SM-Lmod) have been found in many tissues containing smooth muscle by protein immunoblot and immunofluorescence microscopy. Both proteins cofractionate ...

The volitional control of muscle contraction and relaxation is a fundamental component of human motor activity, but how the processing of the subcortical networks, including the subthalamic nucleus (STN), is involved in voluntary muscle contraction (VMC) and voluntary muscle relaxation (VMR) remains unclear. In this study, local field potentials (LFPs) of bilateral STNs were recorded in patient...

Striated muscle tropomyosin (TM) plays an essential role in sarcomeric contraction and relaxation through its regulated movement on the thin filament. Previous work in our laboratory established that alpha- and beta-TM isoforms elicit physiological differences in sarcomeric performance. To address the significance of isoform-specific troponin T binding regions in TM, in this present work we rep...

BACKGROUND Granulation tissue remodeling and myofibroblastic differentiation are critically important events during wound healing. Tobacco smoking has a detrimental effect in gingival tissue repair. However, studies evaluating the effects of cigarette smoke on these events are lacking. MATERIAL AND METHODS We used gingival fibroblasts cultured within free-floating and restrained collagen gels...

The aim of the present study is to investigate if the nucleus raphe obscurus (NRO) participate in regulating the gallbladder motility in rabbits. Rabbits were fasted for about 20-24 hours. After anesthetization with urethane, an incision was made at the middle of the abdomen and the gallbladder was exposed. A frog bladder connected with force transducer was inserted into the gallbladder through...

In guinea pigs whose pelvic nerves were bilaterally sectioned, afferent stimulation of rectoanal branches of the pelvic nerve (PAS) could produce an intense contraction in the rectum similar to propulsive contractions elicited during defecation. The mechanism of this reflex was analyzed. Rectal contraction by PAS was abolished after transecting the spinal cord at T13 or sectioning the lumbar sp...