Maximisation of the erectile response in the investigation of impotence

R D Mills1, K K Sethia

  • 1The Norfolk and Norwich Hospital, UK.

Abstract

Related Concept Videos

Nitric Oxide Signaling Pathway01:28

Nitric Oxide Signaling Pathway

Nitric oxide (NO), an inorganic gas, acts as a potent second messenger in most animal and plant tissues. NO diffuses out of the cells that produce it and enters the neighboring cells to generate a downstream response. NO synthase (NOS) catalyzes NO production by the deamination of the amino acid arginine. There are three isoforms of NOS. Endothelial cells have endothelial NOS (eNOS), nerve and muscle cells have neuronal NOS (nNOS), and macrophages produce inducible NOS (iNOS) upon exposure to...
Dose-Response Relationship: Overview01:03

Dose-Response Relationship: Overview

Agonists can bind with and activate receptors, resulting in the formation of drug-receptor complexes. Once formed, these complexes catalyze many biochemical processes at the cellular level and subsequently induce a pharmacologic response. The degree of response is directly proportional to the fraction of activated receptors, which in turn, depends on the concentration of the drug at the receptor site as well as the sensitivity of the receptor. An increase in the administered dose contributes to...
Dose-Response Relationship: Potency and Efficacy01:22

Dose-Response Relationship: Potency and Efficacy

The potency of a drug is the measure of its ability to produce a biological response and can be compared by looking at the half-maximum effective concentration or EC50 values of different drugs. A lower EC50 value indicates higher potency of the drug. In the dose–response curve of two antihypertensive drugs, candesartan and irbesartan, a significant difference is observed in their EC50 values. A lower EC50 value for candesartan indicates that it is more potent than irbesartan, as it produces...
Male Sexual Response: Erection & Ejaculation01:17

Male Sexual Response: Erection & Ejaculation

Sexual stimulation can take various forms, such as physical touch and visual or auditory cues. When this happens, the parasympathetic reflex in the sacral portion of the spinal cord is activated. This reflex stimulates the release of nitric oxide (NO), which then dilates the arterioles in the penis, increasing blood flow to the erectile tissues - the corpora cavernosa and corpus spongiosum.
The blood filling the erectile tissues compresses the veins, which helps to prevent blood from leaving...
Pharmacodynamic Models: Emax Drug–Concentration Effect Model01:18

Pharmacodynamic Models: Emax Drug–Concentration Effect Model

The Emax drug-concentration effect model is central to pharmacodynamics in drug discovery and development. This model is predicated on the receptor occupancy theory, which posits that the effect of a drug is directly related to the number of receptors occupied by the drug and the resultant complex formation.The model describes the reversible interaction between a drug (C) and a receptor (R) to form a drug-receptor complex (RC). The kinetics of this interaction are quantified by an equation that...
Urodynamic Studies: Uroflowmetry01:19

Urodynamic Studies: Uroflowmetry

Uroflowmetry is a non-invasive urodynamic test designed to measure various aspects of urination, including volume, flow rate, and the time to void. This test is crucial for diagnosing and assessing conditions such as bladder outlet obstruction, bladder dysfunction, incomplete bladder emptying, incontinence, and urinary tract blockages caused by benign prostatic hyperplasia (BPH) and urethral strictures.Pre-Test Instructions:Before a uroflowmetry test, patients are typically advised to drink...