| receptors, adrenergic | Cell-surface proteins that bind epinephrine and/or norepinephrine with high affinity and trigger intracellular changes. The two major classes of adrenergic receptors, alpha and beta, were originally discriminated based on their cellular actions but now are distinguished by their relative affinity for characteristic synthetic ligands. Adrenergic receptors may also be classified according to the subtypes of g-proteins with which they bind; this scheme does not respect the alpha-beta distinction. (12 Dec 1998) |
|---|---|
| receptors, adrenergic, alpha | One of the two major pharmacological subdivisions of adrenergic receptors. The alpha-beta distinction was originally based on cellular effects of receptor activation but now relies on the relative affinities for certain synthetic ligands. Alpha-adrenergic receptors are further subdivided into several subclasses based on studies of endogenous and cloned receptors. (12 Dec 1998) |
| receptors, adrenergic, alpha-1 | A subclass of alpha-adrenergic receptors (receptors, adrenergic, alpha). Alpha-1 adrenergic receptors can be pharmacologically discriminated, e.g., by their high affinity for the agonist phenylephrine and the antagonist prazosin. They are widespread, with clinically important concentrations in the liver, the heart, vascular, intestinal, and genitourinary smooth muscle, and the central and peripheral nervous systems. (12 Dec 1998) |
| receptors, adrenergic, alpha-2 | A subclass of alpha-adrenergic receptors (receptors, adrenergic, alpha). Alpha-2 adrenergic receptors can be pharmacologically discriminated, e.g., by their high affinity for the agonist clonidine and the antagonist yohimbine. They are found on pancreatic beta cells, platelets, and vascular smooth muscle, as well as both pre- and postsynaptically in the central and peripheral nervous systems. (12 Dec 1998) |
| receptors, adrenergic, beta | One of the two major pharmacologically defined classes of adrenergic receptors. The alpha-beta distinction was originally based on the cellular effects of receptor activation but now relies on the relative affinities for characteristic synthetic ligands. Beta adrenergic receptors are further subdivided based on information from endogenous and cloned receptors. (12 Dec 1998) |
| receptors, adrenergic, beta-1 | A subclass of beta-adrenergic receptors (receptors, adrenergic, beta). Beta-1 adrenergic receptors are equally sensitive to epinephrine and norepinephrine and bind the agonist dobutamine and the antagonist metoprolol with high affinity. They are found in the heart, juxtaglomerular cells, and in the central and peripheral nervous systems. (12 Dec 1998) |
| receptors, adrenergic, beta-2 | A subclass of beta-adrenergic receptors (receptors, adrenergic, beta). Beta-2 adrenergic receptors are more sensitive to epinephrine than to norepinephrine and have a high affinity for the agonist terbutaline. They are widespread, with clinically important roles in skeletal muscle, liver, and vascular, bronchial, gastrointestinal, and genitourinary smooth muscle. (12 Dec 1998) |
| autonomic motor neuron | See: motor neuron. (05 Mar 2000) |
| bipolar neuron | A neuron that has two processes arising from opposite poles of the cell body. (05 Mar 2000) |
| magnocellular neuron | <anatomy, neurology> A neuron in the magnocellular region of the brain. Perhaps the first class of neuron from the central nervous system shown to be sensitive to nerve growth factor (that had previously been thought only to act at the periphery). (18 Nov 1997) |
| ganglionic motor neuron | See: motor neuron. (05 Mar 2000) |
| Mauthner neuron | <biology, marine biology> Large neuron in the mesencephalon of fishes and amphibians. A rare example of an individually identifiable neuron in a vertebrate nervous system. (18 Nov 1997) |
| visceral motor neuron | See: motor neuron. (05 Mar 2000) |
| cell adhesion molecules, neuron-glia | Cell adhesion molecules that mediate neuron-neuron adhesion and neuron-astrocyte adhesion. They are expressed on neurons and schwann cells, but not astrocytes and are involved in neuronal migration, neurite fasciculation, and outgrowth. Ng-cam is immunologically and structurally distinct from ncam (neural cell adhesion molecules). (12 Dec 1998) |
| Golgi type II neuron | <physiology> Nerve cells with short axons which ramify in the gray matter. (05 Mar 2000) |