The role of α1-adrenoceptor subtypes in the regulation of arterial blood pressure

Piascik, Michael T.; Butler, Brent T.; Pruitt, T A

doi:10.1016/0014-2999(90)90327-3

Cited by 23 publications

(3 citation statements)

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“…Several pharmacological and molecular studies (Hanft and Gross, 1989;Minneman et al, 1988;Morrow and Creese, 1986;Piascik et al, 1990;Terman et al, 1990;Wilson and Minneman, 1989) have shown that al-adrenoceptors could be subdivided into three different subtypes, a1 A, a1 B, and a1 C, which could possibly use different biochemical mechanisms for signal transduction (Han et al, 1987a,b;Johnson and Minneman, 1987;Morrow and Creese, 1986). Moreover, it has been proposed recently that Prazosin could be considered at high concentration as a selective antagonist for a2adrenoceptors and particularly for a 2 B and a 2 C subtypes which have very similar but distinct pharmacological profiles (Harrison et al, 1991;Akers et al, 1991).…”

Section: Discussionmentioning

confidence: 99%

Normal distribution of alpha‐1‐adrenoceptors in the rat spinal cord and its modification after noradrenergic denervation: A quantitative autoradiographic study

Roudet

Savasta

Feuerstein

1993

J of Neuroscience Research

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The distribution of alpha 1 (alpha 1)-adrenoceptors along the different segments of the spinal cord (cervical, thoracic, lumbar, and sacral) of normal rats has been studied by quantitative autoradiography using the specific alpha 1-antagonist [3H]Prazosin as a ligand. In addition, the influence of noradrenergic (NA) denervation [obtained either by complete transection of the spinal cord at vertebrae level T8-T9 or by selective lesion of NA spinal cord system carried out by intracisternal injection of 6-hydroxydopamine (6-OHDA)] on eventual variations of alpha 1-adrenoceptor density at spinal cord target cells was studied in parallel. In control rats, the quantitative analysis of alpha 1-adrenoceptor densities revealed a widespread distribution of these receptors along all segments of the spinal cord with a similar pattern in the various subregions of gray matter studied. This distribution of alpha 1-adrenoceptors was quite well correlated with the distribution of NA terminals, when referring to previous descriptions by immunohistochemistry. After 6-OHDA lesion, as well as caudally to the transection, a significant increase of alpha 1-adrenoceptor densities was observed in all spinal subregions thus evidencing supersensitivity. These results suggest that NA may act in the spinal cord, at least partly, via alpha 1-adrenoceptors and that the expression of these receptors could be influenced by NA dysfunction, as demonstrated here through the effects observed in lesioned animals.

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Section: Discussionmentioning

confidence: 99%

Normal distribution of alpha‐1‐adrenoceptors in the rat spinal cord and its modification after noradrenergic denervation: A quantitative autoradiographic study

Roudet

Savasta

Feuerstein

1993

J of Neuroscience Research

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“…This effects of the Pz-agonists terbutaline and fenoterol could be connected with their intracellular CAMP-increasing effects (11) The relaxant effect of the selective a,-antagonist yohimbine could play a role in the blockade of the a,-receptor-linked Ca*'-channels (12), besides the increase in the CAMP level (13). It is very probable that the inhibitory effect of the selective al-antagonist urapidil can be explained by inhibition of those Ca**-channels functionally coupled to the al-receptor subtypes (14). A further explanation may be given the inhibition of endogenous ATP-release by the al-receptor blockers (15).…”

Section: Discussionmentioning

confidence: 99%

Evidence of non-synaptic regulation of postpartum uterine contractility in the rat

Gáspár¹,

Márki²,

Zupkó³

et al. 1998

Life Sciences

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Myometrial tissue rings from postpartum rats (24 h after delivery) were studied in vitro by electric field stimulation, and the alpha1/beta2-adrenoceptor ratio was determined by a radioligand binding technique. Pregnancy-denervated uterine rings were stimulated by long-duration pulses (100 ms). The contractions were inhibited by beta2-agonists (terbutaline and fenoterol) and alpha-antagonists (phentolamine, urapidil and yohimbine) in a concentration-dependent manner. Their effects were not altered by the adrenergic neuron-blocking agent bretylium. The alpha-antagonists (except phentolamine) elicited the same maximal inhibition as the beta2-agonists. Receptor assays revealed that the alpha1/beta2 ratio was about 2 in the measured uteri. It was concluded that the inhibitory effects of alpha-antagonists and beta2-agonists are mediated via non-synaptic adrenoceptors of the denervated postpartum rat uterus. The same inhibitory activity could be explained by the greater amount of alpha-receptors. It is believed that this is the first functional proof of the existence of non-synaptic alpha1-adrenoceptors in smooth muscle.

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“…1993). Interestingly, pharmacological studies have shown a predominant role for ala-adrenoceptors in the maintenance of vascular tone and systemic arterial pressure in rats (Piascik et al 1990; Vargas et al 1993). Thus, it could be speculated that a possible selectivity of YM617 for al-adrenoceptor subtype accounts for the observed difference in al-adrenoceptor binding affinity between the prostate and the aorta of human.…”

Section: Discussionmentioning

confidence: 99%

COMPARATIVE STUDY ON _α1‐ADRENOCEPTOR ANTAGONIST BINDING IN HUMAN PROSTATE AND AORTA

Yamada

Suzuki

Tanaka

et al. 1994

Clin Exp Pharma Physio

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1. Specific binding of [3H]-prazosin in prostatic and aortic membranes of humans was saturable and of high affinity (prostate: apparent dissociation constant, Kd = 0.35 +/- 0.03 nmol/L; aorta: Kd = 0.26 +/- 0.03 nmol/L). The density of [3H]-prazosin binding sites (Bmax) for prostate and aorta was 546 +/- 31 and 61.6 +/- 1.6 fmol/mg protein, respectively. 2. Prazosin, YM617, naftopidil and urapidil competed with [3H]-prazosin for the binding sites in a dose-dependent manner in the prostate and aorta of humans. The binding affinities of these antagonists in both tissues were compared, based on the inhibition constant, Ki. Both prazosin and urapidil showed similar affinity to [3H]-prazosin binding sites in human tissue, whereas YM617 and naftopidil showed approximately a 12 and two times higher affinity, respectively, to alpha 1-adrenoceptor sites of prostate than aorta. 3. The chloroethylclonidine treatment reduced partially the Bmax values for specific [3H]-prazosin binding in the prostate and aorta of humans with little effect on the Kd values. 4. These data suggest that YM617 is a relatively selective antagonist of human prostatic alpha 1-adrenoceptors.

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The role of α1-adrenoceptor subtypes in the regulation of arterial blood pressure

Cited by 23 publications

References 3 publications

Normal distribution of alpha‐1‐adrenoceptors in the rat spinal cord and its modification after noradrenergic denervation: A quantitative autoradiographic study

Normal distribution of alpha‐1‐adrenoceptors in the rat spinal cord and its modification after noradrenergic denervation: A quantitative autoradiographic study

Evidence of non-synaptic regulation of postpartum uterine contractility in the rat

COMPARATIVE STUDY ON _α1‐ADRENOCEPTOR ANTAGONIST BINDING IN HUMAN PROSTATE AND AORTA

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The role of α1-adrenoceptor subtypes in the regulation of arterial blood pressure

Cited by 23 publications

References 3 publications

Normal distribution of alpha‐1‐adrenoceptors in the rat spinal cord and its modification after noradrenergic denervation: A quantitative autoradiographic study

Normal distribution of alpha‐1‐adrenoceptors in the rat spinal cord and its modification after noradrenergic denervation: A quantitative autoradiographic study

Evidence of non-synaptic regulation of postpartum uterine contractility in the rat

COMPARATIVE STUDY ON α1‐ADRENOCEPTOR ANTAGONIST BINDING IN HUMAN PROSTATE AND AORTA

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COMPARATIVE STUDY ON _α1‐ADRENOCEPTOR ANTAGONIST BINDING IN HUMAN PROSTATE AND AORTA