In lower vertebrates, cone retinomotor movements occur in response to changes in lighting conditions and to an endogenous circadian clock. In the light, cone myoids contract, while in the dark, they elongate. In order to test the hypothesis that melatonin and dopamine may be involved in the regulation of cone movement, we have used an in vitro eyecup preparation from Xenopus laevis that sustain...

The vasoconstrictor effects of 9,11-epithio-11,12-methano-thromboxane A2 (STA2) on smooth muscle strips of the rabbit coronary artery have been investigated in vitro. Right coronary artery (RCA) was more responsive to STA2 than either the left anterior descending or the circumflex coronary artery. On endothelium-denuded RCA strips, the sensitivity and responsiveness to STA2 were greater than ob...

Calponin contributes to the regulation of smooth muscle contraction through its interaction with F-actin and inhibition of the actin-activated Mg-ATPase activity of phosphorylated myosin. Previous studies have shown that the contractile agonist acetylcholine induced a direct association of translocated calponin and PKC-alpha in the membrane. In the present study, we have determined the domain o...

Two types of calcium channels signal excitation-contraction (E-C) coupling in striated muscle: dihydropyridine receptors (DHPRs, voltage-gated L-type calcium channels on the transverse tubule) and ryanodine receptors (RyRs, calcium release channels on the sarcoplasmic reticulum). Sarcolemmal depolarization activates the DHPR; subsequently, the RyR is activated and releases calcium that activate...

BACKGROUND AND OBJECTIVE Orthodontic tooth movement requires remodeling of the periodontal tissues. The matrix metalloproteinases (MMPs) degrade the extracellular matrix components of the periodontal ligament, while the tissue inhibitors of metalloproteinases (TIMPs) control their activity. Synthetic MMP inhibitors have been developed to inhibit MMP activity. In this study, periodontal ligament...

In this note we show the somewhat surprising fact that proof of `if part' distinguished characterizations metric completeness due to Kirk, and Suzuki Takahashi, respectively, can be deduced in a straightforward manner from Hu's theorem space is complete if only any Banach contraction on bounded closed subsets thereof has fixed point. We also take advantage approach easily deduce characterizatio...

Vascular endothelial cells (ECs), which regulate vascular tonus, serve as a barrier at the interface of vascular tissue. It is generally believed that alteration of this barrier is correlated with diabetic complications; however, a detailed mechanism has not been elucidated. This study examined alteration of bovine arterial EC functions stimulated by a thromboxane A2 analog (9,11-dideoxy-11 alp...

Electrical field stimulation (EFS) of guinea-pig airways, in vitro, evokes an excitatory nonadrenergic noncholinergic (eNANC) contraction mediated by release of tachykinins from sensory nerve endings. Epinastine (WAL 801CL) is an antihistaminic drug with binding affinity at certain other receptors, including alpha-adrenergic receptors and various serotonin (5-HT) receptor subtypes. It is used i...