Heterogeneity of .BETA.-adrenoceptor in canine veins: Comparison among the facial, portal and saphenous veins.

Tsuru, Hiromichi; Negita, Sumiko

doi:10.1254/jjp.51.385

Cited by 8 publications

(3 citation statements)

References 22 publications

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“…On the other hand, there is evidence that vascular β‐adrenoceptors may not be homogeneous in different vascular beds as well as in different species. For instance, although β 1 ‐adrenoceptors predominate in canine facial vein, in canine saphenous vein β 2 ‐adrenoceptors predominate (Tsuru & Negita, 1989). In rat carotid artery there may be a mixed population of all three subtypes of β‐adrenoceptor (MacDonald et al 1999).…”

Section: Discussionmentioning

confidence: 99%

β‐Adrenergic receptor stimulation of L‐type Ca²⁺ channels in rabbit portal vein myocytes involves both αs and βγ G protein subunits

Zhong

Hume

Keef

2001

The Journal of Physiology

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Previous studies have shown that purified G protein αs and βγ subunits stimulate vascular L‐type Ca2+ channels through protein kinase A and C (PKA and PKC), respectively. The present study tested whether activation of endogenous G proteins via β‐adrenergic receptor binding also stimulates vascular Ca2+ channels through both Gαs and Gβγ and the subsequent activation of PKA and PKC. Peak Ba2+ current (IBa) in freshly isolated rabbit portal vein smooth muscle cells was significantly increased by bath application of 0.5 μm isoproterenol (isoprenaline; ISO) when measured using the whole‐cell patch clamp method (53 ± 3 % increase, n= 15). Stimulation of IBa by ISO was partially reversed by a PKA inhibitor, KT 5720, or a PKC inhibitor, calphostin C, and completely blocked when cells were pretreated with both KT 5720 and calphostin C. Dialysis of cells with polyclonal antibody to Gαs significantly reduced but did not completely eliminate ISO‐induced stimulation of IBa. The remaining stimulation was abolished by calphostin C. Dialysis of cells with a polyclonal antibody to Gβ also significantly reduced ISO‐induced stimulation and the remaining stimulation was abolished by KT 5720. Dialysis of cells with both antibodies completely prevented the stimulation of IBa by ISO. ISO‐induced stimulation of IBa was reversed by ICI‐118,551, a specific β2‐adrenoceptor antagonist, but not by CGP 20712A, a specific β1‐adrenoceptor antagonist. In addition, the β2‐adrenoceptor agonist zinterol significantly increased peak IBa while the β1‐adrenoceptor agonist dobutamine and β3‐adrenoceptor agonist BRL 37344A had little effect on peak IBa. These data suggest that β‐adrenergic receptor stimulation of vascular L‐type Ca2+ channels involves both αs and βγ G‐protein subunits, which exert their effects through PKA and PKC, respectively.

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Section: Discussionmentioning

confidence: 99%

β‐Adrenergic receptor stimulation of L‐type Ca²⁺ channels in rabbit portal vein myocytes involves both αs and βγ G protein subunits

Zhong

Hume

Keef

2001

The Journal of Physiology

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“…In this way, physiological roles such as blushing in the human (20) and cranial thermoregulation in the rabbit (21) can be explained. Interestingly, >-adrenoceptor-mediated relaxation of the facial vein is mainly mediated by >1-adrenoceptors, as in the heart, and not by > 2-adrenoceptors, as in most smooth muscles, including blood vessels (22). Likewise, the responses of vessels with different receptor types to a transmitter varies quantitatively and even qualitatively.…”

Section: Diversity Of Adrenoceptor Types and Subtypesmentioning

confidence: 99%

Pharmacology and Physiology of Perivascular Nerves Regulating Vascular Function

Tsuru

Tanimitsu

Hirai

2002

Japanese Journal of Pharmacology

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ABSTRACT-Maintenance of blood pressure is mostly dependent on sympathetic "tone", and the sympathetic nerve innervates the entire vascular bed, excepting the capillaries. Although norepinephrine (NE) is the principal neurotransmitter released upon sympathetic nerve stimulation, neuropeptide Y and ATP are cotransmitters in various vascular tissues. In addition, dopamine and epinephrine, as well as acetylcholine, have been shown to be sympathetic neurotransmitters in specific vasculatures. Transmitter NE release is modified by a number of endogenous substances including the transmitter itself. Chronic denervation of the preganglionic fiber induces an increase in NE release per pulse, indicating postganglionic neuronal supersensitivity. So far, three main adrenoceptor types have been shown, =1, =2 and > , each of which is further divided into at least three subtypes, as well as the = 1L-adrenoceptor, a phenotype of the cloned = 1a-adrenoceptor, in the blood vessel. Thus, the response of vessels with different receptor types to a transmitter varies quantitatively and even qualitatively from one vessel to another. The remarkable diversity in the sympathetic innervation mechanism in the vascular system may play an important role in regional variations in the regulation of blood flow. The sympathetic nerve also exerts long-term trophic action on the blood vessel. In conclusion, the sympathetic nervous system plays an important role not only in the regulation of cardiovascular dynamics but in the maintenance of the vessel structure, as well.

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“…The facial veins of several animal species including rabbits, humans, dogs and monkeys exhibit unusual functional features when compared to other peripheral blood vessels (Chiba and Tsukada 1990;Mellander et al 1982;Pegram et al 1976;Tsuru and Negita 1989;Tsuru et al 1998): the restricted buccal portion of the facial vein of these species shows temperature-dependent myogenic contraction in response to stretch and β-adrenoceptor-mediated relaxation in response to transmural nerve stimulation or to exogenously applied noradrenaline (Mellander et al 1982;Pegram et al 1976;Tsuru and Negita 1989). Based on these observations, the facial vein has been postulated to play a role in cranial thermo-regulation in rabbits (Winquist and Bevan 1980) and the emotional blushing reaction in humans (Mellander et al 1982).…”

Section: Introductionmentioning

confidence: 99%

Potentiation of stretch-induced tone in the rabbit facial vein by an isoquinoline derivative, LOE 908

Tanaka

Someya

Tanaka

et al. 2000

Naunyn-Schmiedeberg's Archives of Pharmacology

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The rabbit facial vein exhibits extracellular Ca2+- and temperature-dependent spontaneous myogenic tone in response to stretch. The present study aimed to elucidate pharmacological characteristics of Ca2+ entry mechanisms responsible for the stretch-induced tension development of the rabbit facial vein. Ca2+- and temperature-sensitive vascular tone in response to stretch was refractory to L-type Ca2+ channel blockers such as nifedipine and diltiazem but was abolished by papaverine or SK&F 96365 which blocks both receptor- and store-operated Ca2+ channels. Interestingly, LOE 908, another type of voltage-independent Ca2+-permeable channel blocker, showed augmentation of the stretch-induced vascular tone instead of inhibition. Potentiation by LOE 908 of stretch-induced vascular tone was also extracellular Ca2+-dependent and counteracted by SK&F 96365. Membrane stretch-activated Ca2+ channels in the rabbit facial vein smooth muscle cells may have a unique characteristic that their opening is stimulated by LOE 908 and thus is distinguishable from other voltage-independent Ca2+-permeable channels.

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Heterogeneity of .BETA.-adrenoceptor in canine veins: Comparison among the facial, portal and saphenous veins.

Cited by 8 publications

References 22 publications

β‐Adrenergic receptor stimulation of L‐type Ca²⁺ channels in rabbit portal vein myocytes involves both αs and βγ G protein subunits

β‐Adrenergic receptor stimulation of L‐type Ca²⁺ channels in rabbit portal vein myocytes involves both αs and βγ G protein subunits

Pharmacology and Physiology of Perivascular Nerves Regulating Vascular Function

Potentiation of stretch-induced tone in the rabbit facial vein by an isoquinoline derivative, LOE 908

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Heterogeneity of .BETA.-adrenoceptor in canine veins: Comparison among the facial, portal and saphenous veins.

Cited by 8 publications

References 22 publications

β‐Adrenergic receptor stimulation of L‐type Ca2+ channels in rabbit portal vein myocytes involves both αs and βγ G protein subunits

β‐Adrenergic receptor stimulation of L‐type Ca2+ channels in rabbit portal vein myocytes involves both αs and βγ G protein subunits

Pharmacology and Physiology of Perivascular Nerves Regulating Vascular Function

Potentiation of stretch-induced tone in the rabbit facial vein by an isoquinoline derivative, LOE 908

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β‐Adrenergic receptor stimulation of L‐type Ca²⁺ channels in rabbit portal vein myocytes involves both αs and βγ G protein subunits

β‐Adrenergic receptor stimulation of L‐type Ca²⁺ channels in rabbit portal vein myocytes involves both αs and βγ G protein subunits