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Cardiotonic
A cardiac stimulant is a substance which acts as a stimulant of the heart – e.g., via positive chronotropic or inotropic action. Examples of cardiac stimulant drugs are cocaine and methamphetamine Methamphetamine (contracted from ) is a potent central nervous system (CNS) stimulant that is mainly used as a recreational drug and less commonly as a second-line treatment for attention deficit hyperactivity disorder and obesity. Methamp .... References External links * {{cardiovascular-system-drug-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heart
The heart is a muscular Organ (biology), organ in most animals. This organ pumps blood through the blood vessels of the circulatory system. The pumped blood carries oxygen and nutrients to the body, while carrying metabolic waste such as carbon dioxide to the lungs. In humans, the heart is approximately the size of a closed fist and is located between the lungs, in the mediastinum, middle compartment of the thorax, chest. In humans, other mammals, and birds, the heart is divided into four chambers: upper left and right Atrium (heart), atria and lower left and right Ventricle (heart), ventricles. Commonly the right atrium and ventricle are referred together as the right heart and their left counterparts as the left heart. Fish, in contrast, have two chambers, an atrium and a ventricle, while most reptiles have three chambers. In a healthy heart blood flows one way through the heart due to heart valves, which prevent cardiac regurgitation, backflow. The heart is enclosed in a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chronotropic
Chronotropic effects (from ''chrono-'', meaning time, and ''tropos'', "a turn") are those that change the heart rate. Chronotropic drugs may change the heart rate and rhythm by affecting the electrical conduction system of the heart and the nerves that influence it, such as by changing the rhythm produced by the sinoatrial node. Positive chronotropes increase heart rate; negative chronotropes decrease heart rate. A dromotrope affects atrioventricular node (AV node) conduction. A positive dromotrope increases AV nodal conduction, and a negative dromotrope decreases AV nodal conduction. A lusitrope is an agent that affects diastolic relaxation. Many positive inotropes affect preload and afterload. __TOC__ Negative chronotropes Chronotropic variables in systolic myocardial left and right. Left sided systolic chronotropy can be appreciated as Aortic Valve open to close time. Right sided variables are represented by pulmonary valve open to close time. Inverted as diastolic ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inotropic
An inotrope is an agent that alters the force or energy of muscular contractions. Negatively inotropic agents weaken the force of muscular contractions. Positively inotropic agents increase the strength of muscular contraction. The term ''inotropic state'' is most commonly used in reference to various drugs that affect the strength of contraction of heart muscle. However, it can also refer to pathological conditions. For example, enlarged heart muscle can increase inotropic state, whereas dead heart muscle can decrease it. Medical uses Both positive and negative inotropes are used in the management of various cardiovascular conditions. The choice of agent depends largely on specific pharmacological effects of individual agents with respect to the condition. One of the most important factors affecting inotropic state is the level of calcium in the cytoplasm of the muscle cell. Positive inotropes usually increase this level, while negative inotropes decrease it. However, not al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cocaine
Cocaine (from , from , ultimately from Quechua: ''kúka'') is a central nervous system (CNS) stimulant mainly used recreationally for its euphoric effects. It is primarily obtained from the leaves of two Coca species native to South America, '' Erythroxylum coca'' and '' Erythroxylum novogranatense''. After extraction from coca leaves and further processing into cocaine hydrochloride (powdered cocaine), the drug is often snorted, applied topically to the mouth, or dissolved and injected into a vein. It can also then be turned into free base form ( crack cocaine), in which it can be heated until sublimated and then the vapours can be inhaled. Cocaine stimulates the reward pathway in the brain. Mental effects may include an intense feeling of happiness, sexual arousal, loss of contact with reality, or agitation. Physical effects may include a fast heart rate, sweating, and dilated pupils. High doses can result in high blood pressure or high body temperature. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Billman
George Edward Billman (born July 23, 1954) is an American physiologist and professor at Ohio State University. After receiving a Ph.D from the University of Kentucky in 1980, Billman began his professional career at the University of Oklahoma. In 1984, he joined the Ohio State staff, where he became an associate professor in 1990 and a full professor in 1996. Billman's research has focused on cardiovascular function, in particular its role in the induction of ventricular fibrillation (VF). He developed non-invasive methods to study autonomic neural regulation of the heart, using a canine model of sudden cardiac death (SCD). These techniques have subsequently been used in human patients to identify people at high risk for VF. Billman has used his sudden cardiac death models to study the effects of exercise training on susceptibility to SCD and the effects of omega-3 fatty acids, among other things. Due to his use of live animals in experiments, Billman has been criticized by anim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methamphetamine
Methamphetamine (contracted from ) is a potent central nervous system (CNS) stimulant that is mainly used as a recreational drug and less commonly as a second-line treatment for attention deficit hyperactivity disorder and obesity. Methamphetamine was discovered in 1893 and exists as two enantiomers: levo-methamphetamine and dextro-methamphetamine. ''Methamphetamine'' properly refers to a specific chemical substance, the racemic free base, which is an equal mixture of levomethamphetamine and dextromethamphetamine in their pure amine forms. It is rarely prescribed over concerns involving human neurotoxicity and potential for recreational use as an aphrodisiac and euphoriant, among other concerns, as well as the availability of safer substitute drugs with comparable treatment efficacy such as Adderall and Vyvanse. Dextromethamphetamine is a stronger CNS stimulant than levomethamphetamine. Both racemic methamphetamine and dextromethamphetamine are illicitly trafficked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
