Biomaterial Database

Smooth muscle alpha-2 adrenoceptors mediate vasoconstrictor responses to exogenous norepinephrine and to sympathetic stimulation to a greater extent in spontaneously hypertensive than in Wistar Kyoto rat tail arteries. 1984

I C Medgett, and P E Hicks, and S Z Langer

The alpha adrenoceptor-mediated vasoconstriction in isolated perfused tail arteries from spontaneously hypertensive (SHR) and age matched Wistar Kyoto (WKY) normotensive rats has been examined. Responses induced by periarterial field stimulation, exogenous norepinephrine or the selective alpha-1 adrenoceptor agonist methoxamine were preferentially antagonized by prazosin in both SHR or WKY tail arteries. However, in SHR only, the alpha-2 adrenoceptor antagonist idazoxan (RX 781094) at low concentrations, significantly antagonized responses to periarterial field stimulation and to exogenous norepinephrine. Except at rather high concentrations, idazoxan was inactive as an antagonist of responses induced by methoxamine. The alpha-1 adrenoceptor blocking agent prazosin was a very potent antagonist of the responses induced by periarterial field stimulation and by methoxamine. These results indicate that alpha-2 adrenoceptors predominate in both SHR and WKY tail arteries, but a significant subpopulation of smooth muscle alpha-2 adrenoceptors is present in tail arteries of SHR but not of WKY rats. In contrast to WKY normotensive rats, postjunctional alpha-2 adrenoceptors may also be involved in the vasoconstrictor responses to sympathetic nerve stimulation in tail arteries of SHR.

UI	MeSH Term	Description	Entries
D006973	Hypertension	Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.	Blood Pressure, High,Blood Pressures, High,High Blood Pressure,High Blood Pressures
D008297	Male		Males
D008729	Methoxamine	An alpha-1 adrenergic agonist that causes prolonged peripheral VASOCONSTRICTION.	Methoxamedrin,Methoxamine Hydrochloride,Metoxamine Wellcome,Vasoxin,Vasoxine,Vasoxyl,Vasylox,Hydrochloride, Methoxamine,Wellcome, Metoxamine
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
D011224	Prazosin	A selective adrenergic alpha-1 antagonist used in the treatment of HEART FAILURE; HYPERTENSION; PHEOCHROMOCYTOMA; RAYNAUD DISEASE; PROSTATIC HYPERTROPHY; and URINARY RETENTION.	Furazosin,Minipress,Pratsiol,Prazosin HCL,Prazosin Hydrochloride,HCL, Prazosin,Hydrochloride, Prazosin
D011918	Rats, Inbred SHR	A strain of Rattus norvegicus with elevated blood pressure used as a model for studying hypertension and stroke.	Rats, Spontaneously Hypertensive,Rats, SHR,Inbred SHR Rat,Inbred SHR Rats,Rat, Inbred SHR,Rat, SHR,Rat, Spontaneously Hypertensive,SHR Rat,SHR Rat, Inbred,SHR Rats,SHR Rats, Inbred,Spontaneously Hypertensive Rat,Spontaneously Hypertensive Rats
D011921	Rats, Inbred WKY	A strain of Rattus norvegicus used as a normotensive control for the spontaneous hypertensive rats (SHR).	Rats, Wistar Kyoto,Wistar Kyoto Rat,Rats, WKY,Inbred WKY Rat,Inbred WKY Rats,Kyoto Rat, Wistar,Rat, Inbred WKY,Rat, WKY,Rat, Wistar Kyoto,WKY Rat,WKY Rat, Inbred,WKY Rats,WKY Rats, Inbred,Wistar Kyoto Rats
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
D004146	Dioxanes	Compounds that contain the structure 1,4-dioxane.