Vasodilatation: From 1 Different Sources
n. an increase in the diameter of blood vessels, especially arteries. This results from local vasodilator hormones (e.g. *prostaglandins) or activation of the *vasomotor centre in the brain, which bring about relaxation of the arterial walls and a consequent lowering of blood pressure.
(alpha-adrenergic blocker) a drug that prevents the stimulation of alpha *adrenoceptors at the nerve endings of the sympathetic nervous system by noradrenaline and adrenaline: it therefore causes relaxation of smooth muscle, including widening of arteries (vasodilatation) and a drop in blood pressure. Alpha blockers include *doxazosin, *phentolamine, *phenoxybenzamine, *indoramin, *prazosin, *alfuzosin, and *tamsulosin.... alpha blocker
(calcium antagonist) a drug that inhibits the influx of calcium ions into cardiac and smooth-muscle cells; it therefore reduces the strength of heart-muscle contraction, reduces conduction of impulses in the heart, and causes *vasodilatation. Calcium-channel blockers, which include *amlodipine, *diltiazem, *nicardipine, *nifedipine, and *verapamil, are used to treat angina and high blood pressure.... calcium-channel blocker
a pocket in the wall of the carotid artery, at its division in the neck, containing receptors that monitor blood pressure (see baroreceptor). When blood pressure is raised, impulses travel from the receptors to the vasomotor centre in the brain, which initiates a reflex *vasodilatation and slowing of heart rate to lower the blood pressure to normal.... carotid sinus
any of several peptides that stimulate diuresis (increased urine production) and vasodilatation (widening of blood vessels). They act on the kidney tubules to promote excretion of sodium (natriuresis) and water. Atrial natriuretic peptide (ANP) is produced in the atria of the heart in response to a rise in atrial pressure. Brain natriuretic peptide (BNP) is produced in the brain and the ventricles of the heart, mainly in response to stretching of the ventricular muscle (as occurs in congestive heart failure). Measurement of blood levels of BNP can be used as a diagnostic test for heart failure and also as an indicator of prognosis.... natriuretic peptide
(malignant vasovagal syndrome) recurrent loss of consciousness due to a drop in blood pressure mediated by *vasodilatation, *bradycardia, or a combination of the two. Attacks resemble a simple faint, but can be very disabling because they are much more frequent and severe. Treatment comprises increased fluid and salt intake together with training in postural manoeuvres that may prevent attacks. A variety of drug treatments is available, but these are commonly ineffective. Implantation of a permanent *pacemaker may be required if profound bradycardia is a feature.... neurocardiogenic syncope
n. a drug that has the effect of stimulating the *parasympathetic nervous system. The actions of parasympathomimetic drugs are cholinergic (resembling those of *acetylcholine) and include stimulation of skeletal muscle, *vasodilatation, depression of heart rate, increasing the tension of smooth muscle, increasing secretions (such as saliva), and constricting the pupil of the eye. They are used in the treatment of *myasthenia gravis (see anticholinesterase) and glaucoma (see miotic).... parasympathomimetic
n. a derivative of *prostaglandin H produced by the endothelium lining blood vessel walls. It inhibits blood clotting by preventing platelet aggregation and causes vasodilatation (compare thromboxane A2). *Epoprostenol is a pharmaceutical preparation of prostacyclin.... prostacyclin
n. an increase or decrease in the diameter of blood vessels, particularly the arteries. See vasoconstriction; vasodilatation.... vasomotion
subjective sensations experienced by women around the time of the *menopause, often described as explosions of heat (hot flushes), mostly followed by profuse sweating and sometimes preceded by an undetermined sensation with waking at night. Objective signs are sudden reddening of the skin on the head, neck, and chest and profuse sweating. Physiological changes include peripheral vasodilatation, *tachycardia with normal blood pressure, and raised skin temperature with normal body temperature.... vasomotor symptoms
(vasoactive intestinal peptide) a peptide hormone and neurotransmitter found widely throughout the central nervous system and the gastrointestinal tract. It has numerous actions, including vasodilatation of blood vessels in the gut, reduction of acid secretion by the stomach, and enhanced secretion of electrolytes into the small bowel.... vip
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