Related Experiment Video
Updated: Sep 21, 2026

Measurement of Endothelium-Dependent Vasorelaxation in the Mouse Thoracic Aorta Using Tensometric Small Volume Chamber Myography
Published on: August 12, 2022
Reduction of sympathetic influences on penile erection by phentolamine
1Department of Urology, University of California, School of Medicine, San Francisco.
Abstract:
The lumbosacral sympathetic trunks seem to play a major role in penile detumescence. In animal experiments an erection induced by cavernous nerve stimulation can be abolished by neurostimulation of the canine sympathetic trunks. This canine experiment was designed to study the possible reduction of the sympathetic effect by intravenous injection of phentolamine. The aborted erection by sympathetic trunks stimulation was partially antagonized by phentolamine. The arterial flow to the penis as well as the intracavernous pressure were elevated by this drug. As an expected side effect the systemic arterial blood pressure decreased by 4-14 cm H2O after phentolamine injection.
Related Concept Videos
Nitric Oxide Signaling Pathway
Adrenergic Antagonists: Pharmacological Actions of ɑ-Receptor Blockers
α1-blockers: These drugs inhibit α1-adrenoceptors on smooth muscle cells, resulting in vasodilation. This vasodilation lowers blood pressure, making α1-blockers valuable in treating hypertension. Additionally, α1-blockers effectively address urinary obstruction...
Drugs Affecting Neurotransmitter Release or Uptake
Antihypertensive Drugs: Vasodilators
Treatment for Pulmonary Arterial Hypertension: Phosphodiesterase Inhibitors
Among the PDE5 inhibitors, sildenafil (Revatio) stands out as a competitive and selective inhibitor. It operates by elevating cellular levels of cGMP and augmenting signaling through the cGMP-PKG pathway, promoting vasodilation. Upon oral...
Male Sexual Response: Erection & Ejaculation
The blood filling the erectile tissues compresses the veins, which helps to prevent blood from leaving...

