INTRODUCTION Phentolamine mesylate has been reported to be an effective local anesthetic reversal agent for soft tissue but has not been studied regarding reversal of pulpal anesthesia. The authors conducted a prospective randomized, single-blind study comparing the reversal of pulpal and soft tissue anesthesia when phentolamine was administered at 30 minutes versus 60 minutes after the adminis...

PURPOSE The purpose of this study was to evaluate, using a randomized, double-blind methodology: (1) the safety of phentolamine mesylate (Oraverse) in accelerating the recovery of soft tissue anesthesia following the injection of two percent lidocaine plus 1:100,000 epinephrine in two- to five-year-olds; and (2) efficacy in four- to five-year-olds only. METHODS One hundred fifty pediatric den...

The question regarding the existence of an alpha-adrenergic component of pial arterial tone was investigated using a microapplication technique combined with the measurement of vascular diameter. Concentration-response curves for the alpha-receptor blocker, phentolamine, revealed no vascular reaction for a concentration range from 2.5 x 10(-11) to 2.5 x 10(-7) M. At higher concentrations (up to...

The ATP-sensitive K+-channel (KATP channel) plays a key role in insulin secretion from pancreatic beta cells. It is closed both by glucose metabolism and the sulfonylurea drugs that are used in the treatment of noninsulin-dependent diabetes mellitus, thereby initiating a membrane depolarization that activates voltage-dependent Ca2+ entry and insulin release. The beta cell KATP channel is a comp...

The pre- and post-junctional alpha-adrenoceptor blocking agent, phentolamine, was given by intravenous infusion to eight healthy volunteers during rest, forearm exercise and post-exercise. Phentolamine produced a sustained increase in heart rate. The diastolic blood pressure decreased slightly whereas systolic and mean blood pressures remained unchanged. Phentolamine caused a marked increase in...

Fetal responses to acute hypoxemia include bradycardia, increase in blood pressure, and peripheral vasoconstriction. Peripheral vasoconstriction contributes to the redistribution of the cardiac output away from ancillary vascular beds toward myocardial, cerebral, and adrenal circulations. We investigated the effect of alpha-adrenergic receptor blockade on this fetal response. Fluorescent micros...

Mulder, A. L. M., C. A. van Goor, D. A. Giussani, and C. E. Blanco. a-Adrenergic contribution to the cardiovascular response to acute hypoxemia in the chick embryo. Am J Physiol Regulatory Integrative Comp Physiol 281: R2004–R2010, 2001.—Fetal responses to acute hypoxemia include bradycardia, increase in blood pressure, and peripheral vasoconstriction. Peripheral vasoconstriction contributes to...

OBJECTIVES The study aimed to evaluate the role of alpha-adrenergic mechanisms during dynamic exercise in both normal and stenotic coronary arteries. BACKGROUND Paradoxical vasoconstriction of stenotic coronary arteries has been reported during dynamic exercise and may be due to several factors such as alpha-adrenergic drive, a decreased release of nitric oxide, platelet aggregation with rele...