Biomaterial Database

Evidence for postjunctional vascular alpha 2-adrenoceptors in peripheral vascular regulation in man. 1983

H L Elliott, and J L Reid

Preliminary studies in healthy normotensive subjects with a selective alpha 2-adrenoceptor antagonist 2-[2-(1,4-benzodioxanyl)]-2-imidazoline (RX781094) in a dose of 0.2 microgram/kg intravenously are described. There was a transient increase in blood pressure, and plasma noradrenaline, 10-20 min after dosing and an associated reduction in heart rate. These observations are consistent with blockade of peripheral presynaptic alpha 2-adrenoceptors in man. The pressor responses to alpha-methylnoradrenaline, which has relatively selective agonist effects on alpha 2-adrenoceptors, were markedly attenuated between 0.5 and 3.0 h after dosing (dose ratio greater than 20). The pressor responsiveness to intravenous phenylephrine, a selective alpha 1-adrenoceptor agonist, was only slightly reduced (dose ratio 1.7 +/- 0.8), as was the blood pressure rise after intravenous noradrenaline (dose ratio 1.7 +/- 0.7). The differential effects on the agonist pressor responses are consistent with antagonism by RX781094 of post-junctional alpha 2-adrenoceptors on vascular smooth muscle.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D008771	Nordefrin	A norepinephrine derivative used as a vasoconstrictor agent.	Methylnorepinephrine,3,4-Dihydroxynorephedrine,4-(2-Amino-1-hydroxypropyl)-1,2-benzenediol,4-(2-Amino-1-hydroxypropyl)-1,2-benzenediol Hydrochloride, (R,R)-(+,-)-Isomer,4-(2-Amino-1-hydroxypropyl)-1,2-benzenediol Hydrochloride, (R,S)-(+-)-Isomer,4-(2-Amino-1-hydroxypropyl)-1,2-benzenediol Tartrate, (R,R), (R,R)-Isomer,4-(2-Amino-1-hydroxypropyl)-1,2-benzenediol Tartrate, (R,S), (R,R)-Isomer,4-(2-Amino-1-hydroxypropyl)-1,2-benzenediol, (R,R)-Isomer,4-(2-Amino-1-hydroxypropyl)-1,2-benzenediol, (R,S)-Isomer,Cobefrine,Corbadrine,Levonordefrin,Neo-Cobefrin,Nordefrin Hydrochloride,Nordefrin Hydrochloride, (R,R)-(+,-)-Isomer,Nordefrin Hydrochloride, (R,S)-(+,-)-Isomer,Nordefrin Tartrate, (R,R), (R,R) Isomer,Nordefrin Tartrate, (R,S), (R,R) Isomer,Nordefrin, (R,R)-Isomer,Nordefrin, (R,S)-Isomer,Norephrine,alpha-Methylnoradrenaline,alpha-Methylnorepinephrine,3,4 Dihydroxynorephedrine,Hydrochloride, Nordefrin,Neo Cobefrin,NeoCobefrin,alpha Methylnoradrenaline,alpha Methylnorepinephrine
D009131	Muscle, Smooth, Vascular	The nonstriated involuntary muscle tissue of blood vessels.	Vascular Smooth Muscle,Muscle, Vascular Smooth,Muscles, Vascular Smooth,Smooth Muscle, Vascular,Smooth Muscles, Vascular,Vascular Smooth Muscles
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
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
D001794	Blood Pressure	PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.	Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic
D004147	Dioxins	A family of compounds that contain the 1,4-dioxin structure. Many specific dioxin derivatives are listed as CARCINOGENS; TERATOGENS; or MUTAGENS.	Dioxin
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man