Biomaterial Database

Pharmacological characterization of presynaptic alpha-adrenoceptors modulating [3H]noradrenaline and [3H]5-hydroxytryptamine release from slices of the hippocampus of the rat. 1982

A L Frankhuyzen, and A H Mulder

The experiments served to characterize the receptors mediating the inhibitory effect of alpha-adrenergic drugs on K+ (20 mM)-induced [3H]noradrenaline (NA) and [3H]5-hydroxytryptamine ([3H]5-HT) release from slices of the dorsal part of rat hippocampus. Dose-response curves were constructed using the cumulative dose-response technique (Frankhuyzen and Mulder, 1981). All of the adrenergic agonist drugs examined inhibited the K+-induced [3H]NA release. NA appeared to have the highest intrinsic activity followed by adrenaline. Clonidine and adrenaline had similar intrinsic activities, while that of oxymetazoline was lowest. The highest pD2 values were observed for oxymetazoline and clonidine, being slightly higher than that of adrenaline followed by NA. By far the lowest pD2 values was observed for phenylephrine. With the exception of phenylephrine, all of the agonists also inhibited the K+-induced [3H]5-HT release. NA, adrenaline and oxymetazoline appeared to have similar intrinsic activities, while that of clonidine was considerably lower. The pD2 values of NA and adrenaline were not significantly different but were somewhat lower than those of oxymetazoline and clonidine. Similar antagonistic effects of phentolamine and yohimbine were observed with respect to the adrenergic inhibition of K+-induced [3H]NA and [3H]5-HT release. Prazosin, however, appeared to be ineffective in both instances. It is concluded from these results that the presynaptic adrenergic inhibiton of [3H]NA as well as [3H]5-HT release is mediated by alpha 2-adrenoceptors located on noradrenergic and serotonergic varicosities, respectively. Furthermore, our data suggest that these alpha 2-adrenoceptors are not pharmacologically identical.

UI	MeSH Term	Description	Entries
D008297	Male		Males
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
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011941	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.	Adrenergic Receptors,Adrenoceptor,Adrenoceptors,Norepinephrine Receptor,Receptors, Epinephrine,Receptors, Norepinephrine,Adrenergic Receptor,Epinephrine Receptors,Norepinephrine Receptors,Receptor, Adrenergic,Receptor, Norepinephrine
D011942	Receptors, Adrenergic, alpha	One of the two major pharmacological subdivisions of adrenergic receptors that were originally defined by the relative potencies of various adrenergic compounds. The alpha receptors were initially described as excitatory receptors that post-junctionally stimulate SMOOTH MUSCLE contraction. However, further analysis has revealed a more complex picture involving several alpha receptor subtypes and their involvement in feedback regulation.	Adrenergic alpha-Receptor,Adrenergic alpha-Receptors,Receptors, alpha-Adrenergic,alpha-Adrenergic Receptor,alpha-Adrenergic Receptors,Receptor, Adrenergic, alpha,Adrenergic alpha Receptor,Adrenergic alpha Receptors,Receptor, alpha-Adrenergic,Receptors, alpha Adrenergic,alpha Adrenergic Receptor,alpha Adrenergic Receptors,alpha-Receptor, Adrenergic,alpha-Receptors, Adrenergic
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
D004305	Dose-Response Relationship, Drug	The relationship between the dose of an administered drug and the response of the organism to the drug.	Dose Response Relationship, Drug,Dose-Response Relationships, Drug,Drug Dose-Response Relationship,Drug Dose-Response Relationships,Relationship, Drug Dose-Response,Relationships, Drug Dose-Response
D006624	Hippocampus	A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.	Ammon Horn,Cornu Ammonis,Hippocampal Formation,Subiculum,Ammon's Horn,Hippocampus Proper,Ammons Horn,Formation, Hippocampal,Formations, Hippocampal,Hippocampal Formations,Hippocampus Propers,Horn, Ammon,Horn, Ammon's,Proper, Hippocampus,Propers, Hippocampus,Subiculums
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012701	Serotonin	A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.	5-HT,5-Hydroxytryptamine,3-(2-Aminoethyl)-1H-indol-5-ol,Enteramine,Hippophaine,Hydroxytryptamine,5 Hydroxytryptamine