Biomaterial Database

Blockade of serotonin receptors on autonomic neurones by (-)-cocaine and some related compounds. 1979

J R Fozard, and A T Mobarok Ali, and G Newgrosh

The interaction between (--)-cocaine and responses to 5-HT elicited through serotonin receptors on autonomic neurones has been investigated on the rabbit heart and the guinea-pig ileum. Low concentrations of (--)-cocaine or its stereoisomer, (4)-pseudococaine, produced shifts to the right of the 5-HT dose-response curves on heart and ileum with no depression of the maximum responses to electrical stimulation or dimethylphenylpiperazinium remained unaffected. A Schild analysis of data obtained on heart and ileum indicated competitive antagonism of 5-HT by (--)-cocaine. Antagonism of 5-HT by the cocaine isomers cannot be ascribed to local anaesthesia per se since neither lignocaine, tetracaine, benzocaine nor bu tacaine were selective antagonists of 5-HT. Similarly, inhibition of monoamine uptake seems of minimal relevance since desipramine proved only a weak antagonist of 5-HT on the heart and did not influence the 5-HT antagonist potency of (--)-cocaine. Selective blockade of 5-HT neuronal responses is a property shared by several structural analogues of (--)-cocaine and (+)-pseudococaine; nor-(--)-cocaine proved the most potent of these, being active at a concentration of 2 x 10(-8) M. These data indicate that (--)-cocaine and several of its derivatives inhibit 5-HT stimulation of both adrenergic and cholinergic autonomic neurones through competition with the agonist at serotonin receptor sties. Since morphine, the tool normally used to identify responses mediated through neuronal serotonin receptors, acts only at certain "morphine-sensitive" junctions and then, non-discriminately, the cocaine analogues, and particularly nor-(--)-cocaine would seem to offer real advantages as tools for differentiating such responses.

UI	MeSH Term	Description	Entries
D007082	Ileum	The distal and narrowest portion of the SMALL INTESTINE, between the JEJUNUM and the ILEOCECAL VALVE of the LARGE INTESTINE.
D008297	Male		Males
D009119	Muscle Contraction	A process leading to shortening and/or development of tension in muscle tissue. Muscle contraction occurs by a sliding filament mechanism whereby actin filaments slide inward among the myosin filaments.	Inotropism,Muscular Contraction,Contraction, Muscle,Contraction, Muscular,Contractions, Muscle,Contractions, Muscular,Inotropisms,Muscle Contractions,Muscular Contractions
D009130	Muscle, Smooth	Unstriated and unstriped muscle, one of the muscles of the internal organs, blood vessels, hair follicles, etc. Contractile elements are elongated, usually spindle-shaped cells with centrally located nuclei. Smooth muscle fibers are bound together into sheets or bundles by reticular fibers and frequently elastic nets are also abundant. (From Stedman, 25th ed)	Muscle, Involuntary,Smooth Muscle,Involuntary Muscle,Involuntary Muscles,Muscles, Involuntary,Muscles, Smooth,Smooth Muscles
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
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
D011817	Rabbits	A burrowing plant-eating mammal with hind limbs that are longer than its fore limbs. It belongs to the family Leporidae of the order Lagomorpha, and in contrast to hares, possesses 22 instead of 24 pairs of chromosomes.	Belgian Hare,New Zealand Rabbit,New Zealand Rabbits,New Zealand White Rabbit,Rabbit,Rabbit, Domestic,Chinchilla Rabbits,NZW Rabbits,New Zealand White Rabbits,Oryctolagus cuniculus,Chinchilla Rabbit,Domestic Rabbit,Domestic Rabbits,Hare, Belgian,NZW Rabbit,Rabbit, Chinchilla,Rabbit, NZW,Rabbit, New Zealand,Rabbits, Chinchilla,Rabbits, Domestic,Rabbits, NZW,Rabbits, New Zealand,Zealand Rabbit, New,Zealand Rabbits, New,cuniculus, Oryctolagus
D011985	Receptors, Serotonin	Cell-surface proteins that bind SEROTONIN and trigger intracellular changes which influence the behavior of cells. Several types of serotonin receptors have been recognized which differ in their pharmacology, molecular biology, and mode of action.	5-HT Receptor,5-HT Receptors,5-Hydroxytryptamine Receptor,5-Hydroxytryptamine Receptors,Receptors, Tryptamine,Serotonin Receptor,Serotonin Receptors,Tryptamine Receptor,Tryptamine Receptors,Receptors, 5-HT,Receptors, 5-Hydroxytryptamine,5 HT Receptor,5 HT Receptors,5 Hydroxytryptamine Receptor,5 Hydroxytryptamine Receptors,Receptor, 5-HT,Receptor, 5-Hydroxytryptamine,Receptor, Serotonin,Receptor, Tryptamine,Receptors, 5 HT,Receptors, 5 Hydroxytryptamine
D003042	Cocaine	An alkaloid ester extracted from the leaves of plants including coca. It is a local anesthetic and vasoconstrictor and is clinically used for that purpose, particularly in the eye, ear, nose, and throat. It also has powerful central nervous system effects similar to the amphetamines and is a drug of abuse. Cocaine, like amphetamines, acts by multiple mechanisms on brain catecholaminergic neurons; the mechanism of its reinforcing effects is thought to involve inhibition of dopamine uptake.	Cocaine HCl,Cocaine Hydrochloride,HCl, Cocaine,Hydrochloride, Cocaine
D003891	Desipramine	A tricyclic dibenzazepine compound that potentiates neurotransmission. Desipramine selectively blocks reuptake of norepinephrine from the neural synapse, and also appears to impair serotonin transport. This compound also possesses minor anticholinergic activity, through its affinity to muscarinic receptors.	Desmethylimipramine,Apo-Desipramine,Demethylimipramine,Desipramine Hydrochloride,Norpramin,Novo-Desipramine,Nu-Desipramine,PMS-Desipramine,Pertofran,Pertofrane,Pertrofran,Petylyl,Ratio-Desipramine,Apo Desipramine,Hydrochloride, Desipramine,Novo Desipramine,Nu Desipramine,PMS Desipramine,Ratio Desipramine