PURPOSE To determine the involvement of noradrenergic and other vasoconstrictor nerves in the contraction of ocular arteries and the modification by cholinergic and nitroxidergic nerves of vasoconstrictor nerve function. METHODS Changes in isometric tension were recorded in helical strips of the canine posterior ciliary and external ophthalmic arteries denuded of the endothelium, which were s...

Protease-activated receptor (PAR)-2 is expressed in endothelial cells and vascular smooth muscle cells. It plays a crucial role in regulating blood pressure via the modulation of peripheral vascular tone. Although some reports have suggested involvement of a neurogenic mechanism in PAR-2-induced hypotension, the accurate mechanism remains to be elucidated. To examine this possibility, we invest...

Airway smooth muscle (ASM) contracts partly due to an increase in cytosolic Ca(2+). In this work, we found that the contraction caused by histamine depends on external Na(+), possibly involving nonselective cationic channels (NSCC) and the Na(+)/Ca(2+) exchanger (NCX). We performed various protocols using isometric force measurement of guinea pig tracheal rings stimulated by histamine. We obser...

LEE, J, S. Contraction of villi and fluid transport in dog jejunal mucosa in vitro. Am. J. Physiol. 221(2) : 488-495. 1971.-An intestinal mucosal membrane preparation permitting simultaneous determination of the fluid transport rate and a microscopic examination of villi was employed. The occurrence of sustained villus shortening was invariably associated with diminution or abolition of fluid t...

OBJECTIVE The vasa vasorum form a network of microvessels in and around the walls of large blood vessels and are thought to be necessary to delivery oxygenated blood to the outer parts of the vessel wall that are inadequately nourished by diffusion from luminal blood. This study was undertaken to investigate directly the mechanisms which control tone in the vasa vasorum. METHODS Arterial vasa...

Nebulized amiloride has been proposed as therapy in cystic fibrosis to block Na+ hyperabsorption in airway epithelium and prevent dehydration of secretions. Patients with cystic fibrosis often have reactive airways. Bovine and canine trachea relax to amiloride in vitro, suggesting another benefit as a bronchodilator, whereas guinea pig trachea, a useful model of human airways, does not. We hypo...

Bradykinin (BK) plays an important role in different physiological processes including the general preservation and modulation of vascular systems. The present study was designed in order to examine the effect of BK on isolated rat femoral artery rings and to investigate the participation of intact endothelium, cyclooxygenase products, Ca(2+) channels, Na(+)/K(+)-ATPase, and B2 kinin receptors ...

The effect of bassianolide (BASS), a cyclodepsipeptide, was investigated on mechanical response, membrane potential, intracellular Na and K contents and 45Ca uptake in response to acetylcholine (ACh) in guinea-pig taenia coli. BASS (10(-5) M) as well as verapamil (5 X 10(-7) M) and papaverine (3 X 10(-5) M) selectively inhibited the tonic component of the contraction induced by ACh (10(-5) M), ...

Cytoplasmic free Ca2+ ([Ca2+]cyt) is essential for the contraction and relaxation of blood vessels. The role of plasma membrane Na+/Ca2+ exchange (NCX) activity in the regulation of vascular Ca2+ homeostasis was previously ascribed to the NCX1 protein. However, recent studies suggest that a relatively newly discovered K+-dependent Na+/Ca2+ exchanger, NCKX (gene family SLC24), is also present in...

The permeability properties of the inner membrane of mung bean mitochondria were studied by osmotic swelling techniques. Rapid mitochondrial swelling was observed in isotonic ammonium phosphate, which indicated that an active phosphate/hydroxyl antiporter was present. The phosphate carrier was specifically inhibited by sulfhydryl reagents. Mitochondria did not swell in isotonic ammonium salts o...