Vasodilator

Information about Vasodilator

A vasodilator is a drug or chemical that relaxes the smooth muscle in blood vessels, which causes them to dilate. Dilation of arterial blood vessels (mainly arterioles) lead to a decrease in blood pressure.

Mechanism and physiology

The mechanism involves the direct relationship between Mean Arterial Pressure and Cardiac Output and Total Peripheral Resistance(TPR). An increase in either of these physiological components causes a rise in the mean arterial pressure. Vasodilators work to decrease TPR and blood pressure through relaxation of smooth muscle cells.^[1] The mechanism relies on removing the stimulus for contraction, which depends predominately on intracellular calcium ion concentrations. This includes stimulation of myosin light chain phosphatase and induction of calcium symporters and antiporters that pump calcium ions out of the intracellular compartment.^[2] Vasodilation occurs in superficial blood vessels of warm-blooded animals when their ambient environment is hot; this process diverts the flow of heated blood to the skin of the animal, where heat can be more easily released into the atmosphere. The opposite physiological process is vasoconstriction. These processes are naturally modulated by the organism's Autonomic Nervous System and adrenal glands, both of which secrete catecholamines such as norepinephrine and epinephrine, respectively.

Vasomotor refers to the muscles and nerves controlling the process of vasodilation.

Therapeutic uses of vasodilators

Vasodilators are used to treat conditions such as hypertension, where the patient has an abnormally high blood pressure, as well as angina and congestive heart failure, where a maintaining a lower blood pressure reduces the patient's risk of developing other cardiac problems.^[3] Flushing may be a physiological response to vasodilators.

Natural vasodilators and drugs that exploit them

Absence of high levels of environmental noise
Absence of high levels of illumination
Adenosine
Adenocard - this is primarily used as an anti-arrhythmic.
Alpha blockers (block the constricting effect of adrenaline).
Amyl nitrite and other nitrites are often used recreationally as a vasodilator, causing lightheadedness and a euphoric feeling.
L-Arginine
Atrial natriuretic peptide (ANP) - a weak vasodilator.
Bradykinin
Ethanol
Endothelium-derived hyperpolarizing factor (EDHF)
Histamine
Complement proteins C3a, C4a and C5a work by triggering histamine release from mast cells and basophil granulocytes.
Niacin (nicotinic acid)
Nitric oxide
Glyceryl trinitrate (commonly known as Nitroglycerin)
Isosorbide mononitrate & Isosorbide dinitrate
Pentaerythritol Tetranitrate (PETN)
Sodium nitroprusside
PDE5 inhibitors: these agents indirectly increase the effects of nitric oxide
Sildenafil
Tadalafil
Vardenafil
Platelet activating factor (PAF)
Prostacyclin (PGI₂) as well as other prostaglandins.
Tetrahydrocannabinol (THC) - the major active chemical in marijuana. Its mild vasodilating effects redden the eyes of cannabis smokers.
Theobromine.
Papaverine an alkaloid found in the opium poppy papaver somniferum

References

1. ^ CVPharmacology
2. ^ American Physiological Society
3. ^ CVPharmacology

• • [ e] Major Drug Groups
Gastrointestinal tract (A)	Antacids • Antiemetics • H₂-receptor antagonists • Proton pump inhibitors • Laxatives • Antidiarrhoeals
Blood and blood forming organs (B)	Anticoagulants • Antiplatelets • Thrombolytics
Cardiovascular system (C)	Antiarrhythmics • Antihypertensives • Diuretics • Vasodilators • Antianginals • Beta blockers • Angiotensin converting enzyme inhibitors • Antihyperlipidemics
Skin (D)	Antipruritics
Reproductive system (G)	Hormonal contraception • Fertility agents • Selective estrogen receptor modulators • Sex hormones
Endocrine system (H)	Anti-diabetics • Corticosteroids • Sex hormones • Thyroid hormones
Infections and Infestations (J, P)	Antibiotics • Antivirals • Vaccines • Antifungals • Antiprotozoals • Anthelmintics
Malignant and Immune disease (L)	Anticancer agents • Immunosuppressants
Muscles, Bones, and Joints (M)	Anabolic steroids • Anti-inflammatories • Antirheumatics • Corticosteroids • Muscle relaxants
Brain and Nervous system (N)	Anesthetics • Analgesics • Anticonvulsants • Mood stabilizers • Anxiolytics • Antipsychotics • Antidepressants • Nervous system stimulants
Respiratory system (R)	Bronchodilators • Decongestants • Antihistamines

• • [ e] Vasodilators used in cardiac diseases (C01D)
Quinolone vasodilators	Flosequinan
Others	Itramin tosilate • Prenylamine • Oxyfedrine • Benziodarone • Carbocromen • Hexobendine • Etafenone • Heptaminol • Imolamine • Dilazep • Trapidil • Molsidomine • Efloxate • Cinepazet • Cloridarol • Nicorandil • Linsidomine • Nesiritide

• • [ e] Peripheral vasodilators (C04)
Imidazoline derivatives	Phentolamine - Tolazoline
Niacin and derivatives	Niacin
Purine derivatives	Pentoxifylline
Ergot alkaloids	Ergoloid- Nicergoline
Other peripheral vasodilators	Phenoxybenzamine - Vincamine - Naftidrofuryl

• • [ e] Cardiovascular system, physiology: cardiovascular physiology
Volumes	Preload - Afterload - End-systolic volume - End-diastolic volume - Frank-Starling law of the heart
Interactions	Cardiac output - Wiggers diagram - Pressure volume diagram
Tropism	Chronotropic - Dromotropic - Inotropic
Hemodynamics	Baroreflex - Kinin-kallikrein system - Renin-angiotensin system - Vasoconstrictors - Vasodilators - Compliance - Vascular resistance
Other	Electrical conduction system of the heart (Cardiac action potential)

An arteriole is a small diameter blood vessel that extends and branches out from an artery and leads to capillaries.

Arterioles have thin muscular walls (usually only one to two layers of smooth muscle) and are the primary site of vascular resistance^[1].
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The mean arterial pressure (MAP) is a term used in medicine to describe a notional average blood pressure in an individual. It is defined as the average arterial pressure during a single cardiac cycle.
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Cardiac output (CO) is the volume of blood being pumped by the heart, in particular by a ventricle in a minute.

Normal Output

Cardiac output is equal to the stroke volume (SV) multiplied by the heart rate (HR).
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Total peripheral resistance refers to the cumulative resistance of the thousands of arterioles in the body, or the lungs, respectively. It is approximately equal to the resistance of the arterioles, since the arterioles are the chief resistance vessels in the body.
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A symporter is an integral membrane protein that is involved in active transport of two or more different molecules or ions across a phospholipid membrane such as the plasma membrane in the same direction.
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An antiporter is an integral membrane protein that is involved in active transport of two or more different molecules or ions across a phospholipid membrane such as the plasma membrane in opposite directions.
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Vasoconstriction is a narrowing of the lumen of blood vessels.

Factors

Factors that trigger vasoconstriction are both of exogenous origin, i.e. medication, and as a response from the body itself.

Body mechanisms

Vasoconstriction is a procedure of the body to e.g.
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autonomic nervous system (ANS) (or visceral nervous system) is the part of the peripheral nervous system that acts as a control system, maintaining homeostasis in the body. These maintenance activities are primarily performed without conscious control or sensation.
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In mammals, the adrenal glands (also known as suprarenal glands) are the triangle-shaped endocrine glands that sit on top of the kidneys; their name indicates that position (ad-, "near" or "at" + -renes, "kidneys").
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Catecholamines are chemical compounds derived from the amino acid tyrosine containing catechol and amine groups. Some of them are biogenic amines. Catecholamines are water soluble and are 50% bound to plasma proteins, so they circulate in the bloodstream.
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Norepinephrine (INN)(abbr. norepi or NE) or noradrenaline (BAN) is a catecholamine and a phenethylamine with chemical formula C₈H₁₁NO₃. The natural stereoisomer is L -(−)-(R)-norepinephrine.
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Epinephrine (INN) (IPA: [ˌɛpɪˈnɛfrən]) or adrenaline (European Pharmacopoeia and BAN) (IPA: [əˈdrɛnələn]
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Hypertension
Classification & external resources

ICD-10 I 10. ,I 11. ,I 12. ,
I 13. ,I 15.
ICD-9 401.x

OMIM 145500
DiseasesDB 6330
MedlinePlus 000468
eMedicine med/1106 ped/1097 emerg/267

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Heart failure
Classification & external resources

ICD-10 I 50.0
ICD-9 428.0

DiseasesDB 16209
MedlinePlus 000158
eMedicine med/3552
MeSH D006333

Congestive heart failure (CHF), also called
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This article relies largely or entirely upon a .
Please help [ improve this article] by introducing appropriate of additional sources. ()
This article has been tagged since January 2007.
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Noise pollution (or environmental noise in technical venues) is displeasing human or machine created sound that disrupts the environment. The dominant form of noise pollution is from transportation sources, principally motor vehicles.
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Over-illumination is the presence of lighting intensity (illuminance) beyond that required for a specified activity. Over-illumination was commonly ignored between 1950 and 1995,^[2]
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Adenosine is a nucleoside composed of adenine attached to a ribose (ribofuranose) moiety via a β-N₉-glycosidic bond.

Adenosine plays an important role in biochemical processes, such as energy transfer - as adenosine triphosphate (ATP) and adenosine
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Cardiac arrhythmia
Classification & external resources

Ventricular Fibrillation or V-Fib, an example of cardiac arrhythmia.
ICD-10 I 47. - I 49.
ICD-9 427

DiseasesDB 15206
MedlinePlus 001101

MeSH D001145 Cardiac arrhythmia
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Alpha blockers (also called alpha-adrenergic blocking agents) constitute a variety of drugs which block α₁-adrenergic receptors in arteries and smooth muscles.
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Amyl nitrite is the chemical compound with the formula C₅H₁₁ONO. A variety of isomers are known, but they all feature an amyl group attached to the nitrito functional group.
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Arginine (abbreviated as Arg or R)^[1] is an α-amino acid. The L -form is one of the 20 most common natural amino acids. Its codons are CGU, CGC, CGA and CGG.
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Atrial natriuretic peptide (ANP), atrial natriuretic factor (ANF), or atriopeptin, is a polypeptide hormone involved in the homeostatic control of body water, sodium, and adiposity.
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Bradykinin is a physiologically and pharmacologically active peptide of the kinin group of proteins, consisting of nine amino acids.

Structure

Bradykinin is a 9-amino acid peptide chain.
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Ethanol, also known as ethyl alcohol, drinking alcohol or grain alcohol, is a flammable, colorless, slightly toxic chemical compound, and is best known as the alcohol found in alcoholic beverages.
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Endothelium-derived hyperpolarizing factor or EDHF refers to an unknown compound, secreted by endothelial cells, which leads to nitric oxide- and prostacyclin-independent vasodilation by relaxation of vascular smooth muscle cells.
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Histamine is a biogenic amine involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter.^[1] New evidence also indicates that histamine plays a role in chemotaxis of white blood cells.
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complement system is a biochemical cascade which helps clear pathogens from an organism. It is one part of the larger immune system.

The complement system consists of a number of small proteins found in the blood, normally circulating as inactive zymogens.
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A mast cell (or mastocyte) is a resident cell of several types of tissues and contains many granules rich in histamine and heparin. Although best known for their role in allergy and anaphylaxis, mast cells play an important protective role as well, being intimately
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Basophils are the least common of the granulocytes, representing about 0.01% to 0.3% of circulating leukocytes (white blood cells). They contain large cytoplasmic granules which obscure the cell nucleus under the microscope.
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