The effects of Mg(2+) and nifedipine (Nif) on vasoconstriction and Ca(2+) transients were studied in intact, pressurized rat mesenteric arteries with myogenic tone. Changes in cytosolic Ca(2+) concentration ([Ca(2+)](cyt)) were measured with confocal microscopy in fluo 4-AM loaded, individual myocytes. Myogenic tone was abolished by 10 mM Mg(2+) or 0.3 microM Nif. Contractions induced by 75 mM ...

Zhang, Jin, W. Gil Wier, and Mordecai P. Blaustein. Mg2 blocks myogenic tone but not K -induced constriction: role for SOCs in small arteries. Am J Physiol Heart Circ Physiol 283: H2692–H2705, 2002. First published August 15, 2002; 10.1152/ajpheart.00260.2002.—The effects of Mg2 and nifedipine (Nif) on vasoconstriction and Ca2 transients were studied in intact, pressurized rat mesenteric arteri...

The arterial baroreflex mediates changes in arterial pressure via reflex changes in cardiac output (CO) and regional vascular conductance, and the relative roles may change between rest and exercise and across workloads. Therefore, we quantified the contribution of CO and regional vascular conductances to carotid baroreflex-mediated increases in mean arterial pressure (MAP) at rest and during m...

Previous studies showed noxious unilateral forepaw electrical stimulation surprisingly evoked negative blood-oxygenation-level-dependent (BOLD), cerebral blood flow (CBF), and cerebral blood volume (CBV) fMRI responses in the bilateral striatum whereas the local neuronal spike and c-Fos activities increased. These negative responses are associated with vasoconstriction and appeared to override ...

Although endothelin-1 (ET-1) induces vasoconstriction, it remains unknown whether 17beta-estradiol (E(2)) treatment following trauma-hemorrhage alters these ET-1-induced vasoconstrictive effects. In addition, the role of the specific estrogen receptor (ER) subtypes (ER-alpha and ER-beta) and the endothelium-localized downstream mechanisms of actions of E(2) remain unclear. We hypothesized that ...

Reportedly, during spinal anesthesia, the shivering threshold is reduced approximately 1 degree C but the vasoconstriction threshold remains normal. Such divergence between the shivering and vasoconstriction thresholds is an unusual pattern of thermoregulatory impairment and suggests that the mechanisms of impairment during regional anesthesia may be especially complex. Accordingly, we sought t...

SATO, S. and HASHIMOTO, K. Responses of the Canine Splenic Vascular Bed to Various Biogenic and Foreign Substances . Tohoku J. exp. Med., 1973, 110 (4), 367-375 Responses of dog splenic vascular bed to various compounds administered into the splenic artery were investigated under a constant perfusion pressure. Adrenergic drugs; epinephrine, norepinephrine and dopamine produced a marked vasocons...

The purpose of this study was to determine whether vasoactive intestinal peptide (VIP) modulates vasoconstriction elicited by phenylephrine and ANG II in vivo and, if so, to begin to elucidate the mechanisms underlying this phenomenon. Using intravital microscopy, we found that suffusion of phenylephrine and ANG II elicits significant vasoconstriction in the in situ hamster cheek pouch that is ...

This experimental study aims to test thermal response and the ability acclimatize during discomfort conditions of different age groups. Experiments were conducted in late summer with thirteen participants, including university students older workers, exposed a climate chamber temperature increasing from 22°C 28°C decreasing 16°C, at rate 3.5K/h. Participants adjusted their clothing stay thermal...