The effect of phentolamine on atrioventricular conduction was studied in 6 patients using the technique of recording the His bundle potential. Right atrial pacing was used in order to keep the heart rate constant before and after administration of the drug. Increasing the heart rate by right atrial pacing resulted in a progressive increase in the PH interval, which represents atrial and atriove...

The effects of phentolamine, 0-3 mg/min given intravenously for 15 minutes, on His bundle electrograms were studied in 11 patients with heart disease. Recordings were made at varied heart rates, using atrial pacing. Phentolamine significantly reduced the AH interval in every patient but it had no effect on the HV interval. Functional and effective refractory periods were measured with the use o...

The effects of phentolamine, 0.3 mg/mm given intravetient and it had no effect on the HQ or HS intervals. This nopsly for 15 minutes, on atrioventricular and intravenrepresents ao improvement in conduction through the tricular conduction were studied in seven cardiac patients atrioventricular node. Phentolamine had no effect on aod in four normal subjects. Recordings were made at atrioventricul...

BACKGROUND AND OBJECTIVES Painful phenomenon is one of the most important and complex experiences. Phentolamine is a non-selective alpha-adrenergic antagonist. The objective of this study was to compare the effect of increasing doses of phentolamine into subarachnoid space in rats in the modulation of painful phenomenon. METHODS 84 male Wistar rats were divided into formalin and plantar incis...

Atrial natriuretic peptide (ANP) controls lipolysis in human adipocytes. Lipid mobilization is increased during repeated bouts of exercise, but the underlying mechanisms involved in this process have not yet been delineated. The relative involvement of catecholamine- and ANP-dependent pathways in the control of lipid mobilization during repeated bouts of exercise was thus investigated in subcut...

The role of neuronal regulation of human cardiovascular function remains incompletely elucidated, especially during exercise. Here we, by positron emission tomography, monitored tissue-specific blood flow (BF) changes in nine healthy young men during femoral arterial infusions of norepinephrine (NE) and phentolamine. At rest, the α-adrenoceptor agonist NE reduced BF by ~40%, similarly in muscle...

The relative contributions of a central neural oscillator and of the delay in alpha-adrenergic transmission within the baroreflex loop in the predominance of low-frequency (LF) cardiovascular variability during sympathetic activation in humans are unclear. We measured R-R interval (RR), muscle sympathetic nerve activity (MSNA), blood pressure (BP), and their variability in 10 normal subjects du...

Nineteen patients with chronic low output cardiac failure were studied before, during and after infusion of phentolamine in doses of 10, 20, 30 and 40 microgram/kg/min. Significant reduction of left- and right-sided pressures and increases in cardiac index and heart rate (HR) were present within 15 minutes of starting phentolamine at the 10 microgram/kg/min dose. Minimal additional effect was o...