Biomaterial Database

Supersensitivity to catecholamines after impairment of extraneuronal uptake or catechol-O-methyl transferase. 1975

U Trendelenburg, and K H Graefe

In cat papillary muscle and nictitating membrane block of extraneuronal catechol-O-methyl transferase (COMT) by 3',4'-dihydroxy-alpha-methyl propiophenone (U-0521) or of extraneuronal uptake by hydrocortisone causes supersensitivity to catecholamines whenever the experimental conditions result in a high sensitivity of the organ to catecholamines. After block of monoamine oxidase the extraneuronal O-methylation of (-)-[3H]norepinephrine by the isolated nictiating membrane is due to two O-methylating systems (Km and Vmax: 7.5 muM and 0.73 nmoles - g-1 - min-1, and 131 muM and 8.5 nmoles - g-1 - min-1, respectively). Hydrocortisone (28 muM) blocked the activity of the high affinity system without affecting the low affinity system. Apparently, there exists an extraneuronal compartment of high affinity that has a hydrocortisone-sensitive uptake mechnism; this compartment influences the concentration of catecholamines below the Km of this compartment. Supersensitivity ensues when either uptake or enzyme is blocked. Since the sensitivity effects of U-0521 and hydrocortisone are not additive, the high affinity compartment must a) metabolize most of the catecholamine transported into the compartment, and b) have a limited storage capacity for catecholamines after block of COMT.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008996	Monoamine Oxidase Inhibitors	A chemically heterogeneous group of drugs that have in common the ability to block oxidative deamination of naturally occurring monoamines. (From Gilman, et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p414)	MAO Inhibitor,MAO Inhibitors,Reversible Inhibitors of Monoamine Oxidase,Monoamine Oxidase Inhibitor,RIMA (Reversible Inhibitor of Monoamine Oxidase A),Reversible Inhibitor of Monoamine Oxidase,Inhibitor, MAO,Inhibitor, Monoamine Oxidase,Inhibitors, MAO,Inhibitors, Monoamine Oxidase
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D009541	Nictitating Membrane	A fold of the mucous membrane of the CONJUNCTIVA in many animals. At rest, it is hidden in the medial canthus. It can extend to cover part or all of the cornea to help clean the CORNEA.	Third Eyelid,Eyelid, Third,Eyelids, Third,Membrane, Nictitating,Membranes, Nictitating,Nictitating Membranes,Third Eyelids
D009638	Norepinephrine	Precursor of epinephrine that is secreted by the ADRENAL MEDULLA and is a widespread central and autonomic neurotransmitter. Norepinephrine is the principal transmitter of most postganglionic sympathetic fibers, and of the diffuse projection system in the brain that arises from the LOCUS CERULEUS. It is also found in plants and is used pharmacologically as a sympathomimetic.	Levarterenol,Levonorepinephrine,Noradrenaline,Arterenol,Levonor,Levophed,Levophed Bitartrate,Noradrenaline Bitartrate,Noradrénaline tartrate renaudin,Norepinephrin d-Tartrate (1:1),Norepinephrine Bitartrate,Norepinephrine Hydrochloride,Norepinephrine Hydrochloride, (+)-Isomer,Norepinephrine Hydrochloride, (+,-)-Isomer,Norepinephrine d-Tartrate (1:1),Norepinephrine l-Tartrate (1:1),Norepinephrine l-Tartrate (1:1), (+,-)-Isomer,Norepinephrine l-Tartrate (1:1), Monohydrate,Norepinephrine l-Tartrate (1:1), Monohydrate, (+)-Isomer,Norepinephrine l-Tartrate (1:2),Norepinephrine l-Tartrate, (+)-Isomer,Norepinephrine, (+)-Isomer,Norepinephrine, (+,-)-Isomer
D009647	Normetanephrine	A methylated metabolite of norepinephrine that is excreted in the urine and found in certain tissues. It is a marker for tumors.	3-Methoxynoradrenaline,Normetadrenaline,3 Methoxynoradrenaline
D010210	Papillary Muscles	Conical muscular projections from the walls of the cardiac ventricles, attached to the cusps of the atrioventricular valves by the chordae tendineae.	Muscle, Papillary,Muscles, Papillary,Papillary Muscle
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D002394	Catechol O-Methyltransferase	Enzyme that catalyzes the movement of a methyl group from S-adenosylmethionone to a catechol or a catecholamine.	Catechol Methyltransferase,Catechol-O-Methyltransferase,Catechol O Methyltransferase,Methyltransferase, Catechol,O-Methyltransferase, Catechol
D002415	Cats	The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)	Felis catus,Felis domesticus,Domestic Cats,Felis domestica,Felis sylvestris catus,Cat,Cat, Domestic,Cats, Domestic,Domestic Cat