Vasoconstriction is the narrowing of the blood vessels resulting from contracting of the muscular wall of the vessels. When blood vessels constrict, the flow of blood is restricted or slowed. It is the opposite of vasodilation, the widening of blood vessels. Factors causing vasoconstriction are called vasoconstrictor, also vasopressors or simply pressors. Vasoconstriction usually results in an increase of the blood pressure. Blood pressure is also the title of a short story by Damon Runyan in Guys and Dolls and Other Stories Vasoconstriction may be slight or severe. Many vasoconstrictors also cause pupil dilation. Pupillary response or dilation of the pupil is a physiological response that varies the size of the Pupil of the eye via the Iris dilator muscle. Vasoconstriction in the penis can disable males from maintaining an erection (erectile dysfunction). It may result from disease, medication, or psychological conditions. Medications that cause vasoconstriction include antihistamines, decongestants, methylphenidate (commonly used for ADHD), cough and cold combinations, pseudoephedrine, and caffeine.
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General mechanism
Vasoconstriction is mostly the result of increased intracellular concentration of calcium (Ca2+ions). Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 However, specific mechanisms for generating an increased intracellular concentration of calcium depends on the vasoconstrictor. In any case, this calcium results in contraction of smooth muscle (see Smooth muscle for details), resulting in a constriction of the vessel. Smooth muscle is a type of non- Striated muscle, found within the Tunica media layer of large and small Arteries and Veins, the bladder Smooth muscle is a type of non- Striated muscle, found within the Tunica media layer of large and small Arteries and Veins, the bladder
Factors and individual mechanisms
Factors that trigger vasoconstriction can be of exogenous origin, such as medication and endogenous as well, as a response from the body itself. Vasoconstriction can happen because of the severe heat.
Medication
Examples include amphetamines, antihistamines and cocaine. Amphetamine, and related drugs such as Methamphetamine are a group of drugs that act by increasing levels of Norepinephrine, Serotonin, and Dopamine A histamine antagonist is an agent which serves to inhibit the release or action of Histamine. Cocaine ( benzoylmethyl ecgonine) is a Crystalline Tropane Alkaloid that is obtained from the leaves of the Coca plant Many are used in medicine to treat hypotension and as topical decongestants. In Physiology and Medicine, hypotension refers to an abnormally low Blood pressure. Topical decongestants are Decongestants applied directly to the Nasal cavity. Vasoconstrictors are also used clinically to increase blood pressure or to reduce local blood flow. Blood pressure is also the title of a short story by Damon Runyan in Guys and Dolls and Other Stories
The routes of administration varies. In Pharmacology and Toxicology, a route They may be both systemic and topical. For example, pseudoephedrine is available systemic (i. Pseudoephedrine (commonly abbreviated as PSE is a sympathomimetic Amine commonly used as a Decongestant. e. orally ingested tablets like Sudafed), and topical (such as nose sprays like phenylephrine Neo-synephrine, and eye drops for pupil dilation purposes)
Examples include: "Where are the ↑ ↓ 's ?"
| Vasoconstrictor | Receptor (↑ = opens. Sudafed is a Brand name and registered Trademark for a family of over-the-counter (OTC Decongestants manufactured by Johnson & Johnson Phenylephrine or Neo-Synephrine is an α1-adrenergic receptor Agonist used primarily as a Decongestant, as an agent to dilate the Pupillary response or dilation of the pupil is a physiological response that varies the size of the Pupil of the eye via the Iris dilator muscle. ↓ = closes) |
Transduction (↑ = increases. ↓ = decreases) |
|---|---|---|
| Amphetamines | ||
| Antihistamines | ||
| Cocaine | ||
| Caffeine | ||
| Decongestants | ||
| Ergine | ||
| LSD | ||
| LSA | ||
| Methylphenidate | ||
| Phenylephrine | ||
| Pseudoephedrine | ||
| Stimulants | ||
| Tetrahydrozoline hydrochloride (in eye drops) | ||
| Psilocybin |
Endogenous
Vasoconstriction is a procedure of the body that avoids orthostatic hypotension. Amphetamine, and related drugs such as Methamphetamine are a group of drugs that act by increasing levels of Norepinephrine, Serotonin, and Dopamine A histamine antagonist is an agent which serves to inhibit the release or action of Histamine. Cocaine ( benzoylmethyl ecgonine) is a Crystalline Tropane Alkaloid that is obtained from the leaves of the Coca plant Caffeine is a bitter white crystalline Xanthine Alkaloid that acts as a Psychoactive Stimulant Drug and a mild Diuretic A decongestant is a broad class of Medications used to relieve Nasal congestion. LSA, also known as d-lysergic acid amide, d-lysergamide, ergine, and LA-111, is an Alkaloid of the Ergoline family Phenylephrine or Neo-Synephrine is an α1-adrenergic receptor Agonist used primarily as a Decongestant, as an agent to dilate the Pseudoephedrine (commonly abbreviated as PSE is a sympathomimetic Amine commonly used as a Decongestant. Stimulant drugs are Drugs that temporarily increase alertness and awareness Tetrahydrozoline is a derivative of Imidazoline, which is found in over-the-counter Eye drops and Nasal sprays Other derivatives include Naphazoline Psilocybin (IPA /saɪləˈsaɪbɪn/ (also known as psilocybine) is a psychedelic Indole of the Tryptamine family found in Psilocybin It is a part of a body negative feed back loop in which the body tries to restore homeostasis.
For example, vasoconstriction is a hypothermic preventative in which the blood vessels constrict and blood must move at a higher pressure to actively avoid a hypoxic reaction. ATP is used as a form of energy to increase this pressure to heat the body. Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy Once homeostasis is restored the blood pressure and ATP production regulates.
Vasoconstriction also occurs in superficial blood vessels of warm-blooded animals when their ambient environment is cold; this process diverts the flow of heated blood to the center of the animal, preventing the loss of heat. In Biology, a warm-blooded Animal species is one whose members maintain thermal Homeostasis; that is they keep their body temperature at a roughly constant
| Vasoconstrictor [1] | Receptor (↑ = opens. ↓ = closes) [1] |
Transduction (↑ = increases. ↓ = decreases) [1] |
|---|---|---|
| Stretch | ↑Stretch-activated ion channels | depolarization -->
|
| ATP (intracellular) | ↓ATP-sensitive K+ channel | |
| muscarinic agonists e. Stretch-activated or stretch-gated ion channels are Ion channels which open their Pores in response to mechanical deformation of a Neuron 's In biology depolarization is a decrease in the Absolute value of a cell's Membrane potential. Voltage-dependent calcium channels (VDCC are a group of voltage-gated Ion channels found in excitable cells ( e Sodium channels are Integral membrane proteins that form Ion channels, conducting sodium ions ( Na+) through a cell's Plasma membrane Voltage-dependent calcium channels (VDCC are a group of voltage-gated Ion channels found in excitable cells ( e The sodium-calcium exchanger (often denoted Na+/Ca2+ exchanger, NCX, or exchange protein) is an Antiporter Membrane Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy A muscarinic receptor agonist is an agent that enhances the activity of the Muscarinic acetylcholine receptor. g. acetylcholine |
↑muscarinic receptor M2 | Activation of Gi --> ↓cAMP --> ↓PKA activity --> ↓phosphorylation of MLCK --> ↑MLCK activity --> ↑phosphorylation of MLC (calcium-independent) |
| NPY | NPY receptor | |
| adrenergic agonists e. The Chemical compound acetylcholine (often abbreviated ACh) is a Neurotransmitter in both the Peripheral nervous system (PNS and Central The muscarinic acetylcholine receptor M2, also known as the cholinergic receptor muscarinic 2, is a Muscarinic acetylcholine receptor. Gi alpha subunit (or Gi/G0 or Gi protein) is a Heterotrimeric G protein subunit which inhibits the production of Cyclic adenosine monophosphate ( cAMP, cyclic AMP or 3'-5'-cyclic Adenosine monophosphate) is a Second messenger that is important in many biological In Cell biology, protein kinase A, refers to a family of Enzymes whose activity is dependent on the level of Cyclic AMP (cAMP in the cell Phosphorylation is the addition of a Phosphate (PO4 group to a Protein molecule or a small molecule Myosin-light-chain kinase (MLCK is a serine/threonine-specific protein kinase that Phosphorylates the regulatory light chain of Myosin II. Myosins are a large family of Motor proteins found in Eukaryotic tissues. Neuropeptide Y (NPY is a 36 Amino acid peptide Neurotransmitter found in the Brain and Autonomic nervous system. Neuropeptide Y receptors are a class of G-protein coupled receptors which are activated by the closely related peptide hormones Neuropeptide Y, Peptide YY An adrenergic is a drug, or other substance which has effects similar to or the same as Epinephrine (adrenaline g. norepinephrine |
↑α1 adrenergic receptor | Activation of Gq --> ↑PLC activity --> ↑IP3 and DAG --> activation of IP3 receptor in SR --> ↑intracellular Ca2+ |
| thromboxane | ↑thromboxane receptor | |
| endothelin | ↑endothelin receptor ETA | |
| angiotensin II | ↑Angiotensin receptor 1 |
Activation of Gq --> ↑PLC activity --> ↑IP3 and DAG --> activation of IP3 receptor in SR --> ↑intracellular Ca2+ |
| open VDCCs --> ↑intracellular Ca2+[2] | ||
| ATP (extracellular) | ↑P2X receptor | ↑Ca2+ |
| moderately high levels of stress | - | release of adrenergic agonists |
| Asymmetric dimethylarginine |
Others
| Vasoconstrictor | Mechanism |
|---|---|
| Bright light | |
| Cold (water, air, etc. Norepinephrine ( INN) (abbreviated norepi or NE) or noradrenaline ( BAN) (abbreviated NA or NAd) is a The alpha-1 adrenergic receptor (α1-AR is an Adrenergic receptor with the primary effect of Vasoconstriction. Gq protein or Gq/11 is a Heterotrimeric G protein subunit that activates Phospholipase C (PLC Phospholipase C is a class of Enzymes that cleave Phospholipids just before the Phosphate group (see Figure Inositol trisphosphate or inositol 145-trisphosphate (also commonly known as triphosphoinositol; abbreviated InsP3 or IP3 A diglyceride, or a diacylglycerol (DAG is a Glyceride consisting of two Fatty acid chains covalently bonded to a Glycerol Inositol triphosphate receptor ( IP3R) is a membrane Glycoprotein complex acting as Ca2+ channel activated by Inositol triphosphate The endoplasmic reticulum (Greek endo = "within" (prefix plásma = "formed entity" Latin reticulum = "little net" or ER, is an Organelle Thromboxane is a member of the family of Lipids known as Eicosanoids. The thromboxane receptor is a protein on the surface of cells in the Endothelium of blood vessels and in the Placenta which interacts with the Endothelins are proteins that constrict blood vessels and raise blood pressure There are at least three known Endothelin receptors, ETA ETB1 and ETB2 all of which are G protein-coupled receptors whose activation Angiotensin causes blood vessels to constrict and drives blood pressure up The angiotensin receptors are a class of G protein-coupled receptors with Angiotensins as ligands They are important in the Renin-angiotensin system Gq protein or Gq/11 is a Heterotrimeric G protein subunit that activates Phospholipase C (PLC Phospholipase C is a class of Enzymes that cleave Phospholipids just before the Phosphate group (see Figure Inositol trisphosphate or inositol 145-trisphosphate (also commonly known as triphosphoinositol; abbreviated InsP3 or IP3 A diglyceride, or a diacylglycerol (DAG is a Glyceride consisting of two Fatty acid chains covalently bonded to a Glycerol Inositol triphosphate receptor ( IP3R) is a membrane Glycoprotein complex acting as Ca2+ channel activated by Inositol triphosphate The endoplasmic reticulum (Greek endo = "within" (prefix plásma = "formed entity" Latin reticulum = "little net" or ER, is an Organelle Voltage-dependent calcium channels (VDCC are a group of voltage-gated Ion channels found in excitable cells ( e Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy P2X receptors are a family of cation-permeable ligand gated ion channels that open in response to the binding of extracellular adenosine 5'-triphosphate ( ATP Asymmetric dimethylarginine (ADMA is a naturally occurring chemical found in Blood plasma. Over-illumination is the presence of lighting intensity ( Illuminance) beyond that required for a specified activity ) | |
| Elevated sound levels |
Pathology
Vasoconstriction can be a contributing factor to erectile dysfunction. Noise health effects are the Health consequences of elevated Sound levels Elevated workplace or other Noise can cause Hearing impairment [3]
An increase of blood flow in the penis that builds up causes an erection, however if the body is not functioning properly the blood vessels in the penis activate and allow less blood to pool, meaning the erection goes down prematurely or simply fails to completely go up. This does not necessarily mean that the person in question is not aroused, it is a lapse in judgement between the Central Nervous System [CNS] and the Peripheral Nervous System [PNS] . When blood pools in the penis the body reacts to the excessive heat to cool it, resulting in vasoconstriction.
References
- ^ a b c Unless else specified in box, then ref is: Walter F. , PhD. Boron. Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. ISBN 1-4160-2328-3. Page 479
- ^ Walter F. , PhD. Boron. Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. ISBN 1-4160-2328-3. Page 771
- ^ Richard Milsten and Julian Slowinski, The sexual male,bc,main point W. Male (♂ refers to the sex of an organism or part of an organism which produces small mobile Gametes called spermatozoa. W. Norton Company, New York, London (1999) ISBN 0-393-04740-7
See also
- Addison's disease
- Inotrope
- Hypotension
- Nitric oxide
- Pheochromocytoma
- Shock
- Vasodilation
- Postural orthostatic tachycardia syndrome
External links
- Definition of Vasoconstriction on HealthScout
- Cannabis arteritis revisited--ten new case reports
- Are coronary heart disease and peripheral arterial disease associated with tobacco or cannabis consumption
- Vasoconstrictor effects of Cannabis appear to inhibit Migraine (headache) attacks
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