Related Experiment Video
Updated: Aug 6, 2026
Intracavernosal Pressure Recording to Evaluate Erectile Function in Rodents
Published on: June 6, 2018
Role of alpha adrenergic receptors in erectile function
1Department of Urology, Boston University School of Medicine, Boston, MA 02118, USA.
Abstract:
Penile erection is a complex physiological process in which the regulation of penile hemodynamics depends on signal input from central and peripheral nervous systems, and on the balance and interplay between several local physiological mediators (neurotransmitters, vasoactive agents and endocrine factors). A role for the sympathetic nervous system in attaining or maintaining penile flaccidity and detumescence is well recognized. However, the exact mechanisms of alpha-adrenergic receptor mediated erectile function remain poorly defined. The objective of this review is to summarize data presented in the literature and from our laboratory on alpha-adrenergic receptors, and to discuss the conceptual framework by which the alpha-adrenergic receptor pathway modulates penile corpus cavernosum smooth muscle contractility. We will integrate the current state of knowledge of penile erection into one framework encompassing the biochemical and physiological pathways responsible for trabecular smooth muscle relaxation (erection) and contraction (detumescence). We will focus our discussion on local control mechanisms of alpha-adrenergic receptors and explore the following topics: (1) functional activity of alpha-1 and alpha-2 adrenergic receptors in the physiology of human penile erection; (2) identification, classification and characterization of alpha-1 and alpha-2 adrenergic receptor subtypes in human penile erectile tissue; (3) molecular mechanism of action of alpha-1 and alpha-2 adrenergic receptors in human penile erectile tissue; (4) blockade of alpha-1 and alpha-2 adrenergic receptor action by selective and non-selective alpha-1 and alpha-2 adrenergic receptor antagonists (blockers); (5) physiologic (functional) antagonism of alpha-1 and alpha-2 adrenergic receptor activity by vasodilators mediating smooth muscle relaxation; and (6) key areas of consensus, as well as critical gaps in the existing scientific knowledge concerning the rationale and the potential use of alpha-blockers in erectile function. International Journal of Impotence Research (2000) 12, Suppl 1, S48-63
Related Concept Videos
01:27Adrenergic Receptors (Adrenoceptors): Classification
α-Adrenoceptors
α-Adrenoceptors are classified into two main subtypes: α1 and α2. The α1 adrenoceptors, which are found on postsynaptic...
01:31Adrenergic Receptors: ɑ Subtype
Adrenaline ≥ Noradrenaline >> Isoprenaline
α-adrenoceptors are further divided into α1 and α2-adrenoceptors.
α1-Adrenoceptors: These receptors are located postsynaptically on the effector organs and cause constriction of smooth muscle mediated by activation of phospholipase C—inositol-1,4,5-trisphosphate...
01:26Adrenergic Receptors: β Subtype
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
01:17Adrenergic Antagonists: Chemistry and Classification of ɑ-Receptor Blockers
Nonselective α-blockers: Nonselective α-blockers contain haloalkylamine or imidazoline moieties. Phenoxybenzamine, with a haloalkylamine...
01:22Adrenergic 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...
01:17Male Sexual Response: Erection & Ejaculation
The blood filling the erectile tissues compresses the veins, which helps to prevent blood from leaving...