Biomaterial Database

Local hypothalamic adrenoceptor activation in rat: alpha 1 inhibits and alpha 2 stimulates growth hormone secretion. 1993

J O Willoughby, and I M Chapman, and R Kapoor

Centre for Neuroscience, Flinders University and Medical Centre, Adelaide, Australia.

We made stereotaxic microinjections of adrenoceptor agonists and the catecholamine-releasing agent, tyramine, into the preoptic anterior hypothalamic area (PO/AHA) or the medial basal hypothalamus (MBH) of unstressed rats. Growth hormone (GH) plasma concentrations were measured serially before and after intrahypothalamic injections. Noradrenaline and phenylephrine inhibited GH secretion wherever injected but were effective at lower doses in the PO/AHA. Clonidine stimulated GH secretion at both sites, at several doses in the MBH and only at one dose in the PO/AHA. Tyramine inhibited GH when injected in the PO/AHA, but not in the MBH. We conclude: (a) alpha 1 inhibition is predominant over alpha 2 stimulation of GH on or near somatostatin neurons; (b) alpha 2 stimulation predominates over alpha 1 inhibition of GH on or near GRF neurons, and (c) endogenous catecholamines in the PO/AHA have a predominantly inhibitory effect on GH secretion.

UI	MeSH Term	Description	Entries
D007031	Hypothalamus	Ventral part of the DIENCEPHALON extending from the region of the OPTIC CHIASM to the caudal border of the MAMMILLARY BODIES and forming the inferior and lateral walls of the THIRD VENTRICLE.	Lamina Terminalis,Preoptico-Hypothalamic Area,Area, Preoptico-Hypothalamic,Areas, Preoptico-Hypothalamic,Preoptico Hypothalamic Area,Preoptico-Hypothalamic Areas
D007033	Hypothalamus, Middle	Middle portion of the hypothalamus containing the arcuate, dorsomedial, ventromedial nuclei, the TUBER CINEREUM and the PITUITARY GLAND.	Hypothalamus, Medial,Intermediate Hypothalamic Region,Hypothalamic Region, Intermediate,Hypothalamic Regions, Intermediate,Intermediate Hypothalamic Regions,Medial Hypothalamus,Middle Hypothalamus,Region, Intermediate Hypothalamic,Regions, Intermediate Hypothalamic
D008297	Male		Males
D008845	Microinjections	The injection of very small amounts of fluid, often with the aid of a microscope and microsyringes.	Microinjection
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
D010656	Phenylephrine	An alpha-1 adrenergic agonist used as a mydriatic, nasal decongestant, and cardiotonic agent.	(R)-3-Hydroxy-alpha-((methylamino)methyl)benzenemethanol,Metaoxedrin,Metasympatol,Mezaton,Neo-Synephrine,Neosynephrine,Phenylephrine Hydrochloride,Phenylephrine Tannate,Neo Synephrine,Tannate, Phenylephrine
D011301	Preoptic Area	Region of hypothalamus between the ANTERIOR COMMISSURE and OPTIC CHIASM.	Area Preoptica,Lateral Preoptic Area,Medial Preoptic Area,Preoptic Nuclei,Area Preopticas,Area, Lateral Preoptic,Area, Medial Preoptic,Area, Preoptic,Areas, Lateral Preoptic,Areas, Medial Preoptic,Areas, Preoptic,Lateral Preoptic Areas,Medial Preoptic Areas,Nuclei, Preoptic,Nucleus, Preoptic,Preoptic Area, Lateral,Preoptic Area, Medial,Preoptic Areas,Preoptic Areas, Lateral,Preoptic Areas, Medial,Preoptic Nucleus,Preoptica, Area,Preopticas, Area
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
D003000	Clonidine	An imidazoline sympatholytic agent that stimulates ALPHA-2 ADRENERGIC RECEPTORS and central IMIDAZOLINE RECEPTORS. It is commonly used in the management of HYPERTENSION.	Catapres,Catapresan,Catapressan,Chlophazolin,Clofelin,Clofenil,Clonidine Dihydrochloride,Clonidine Hydrochloride,Clonidine Monohydrobromide,Clonidine Monohydrochloride,Clopheline,Dixarit,Gemiton,Hemiton,Isoglaucon,Klofelin,Klofenil,M-5041T,ST-155,Dihydrochloride, Clonidine,Hydrochloride, Clonidine,M 5041T,M5041T,Monohydrobromide, Clonidine,Monohydrochloride, Clonidine,ST 155,ST155
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