Book ChapterDOI
Characterization of alpha 1- and alpha 2-adrenergic receptors.
TLDR
In this paper, it was shown that α2 receptors may exist in multiple-affinity states reflecting the ability of the α2 binding-site protein to form a complex with additional membrane proteins that themselves are receptors for the physiological substrates guanosine 5'-triphosphate (GTP), Na+, Mg2+, and possibly Ca2+-calmodulin.Abstract:
Publisher Summary
Alpha-1 (α1) receptors by and large appear to occur in a single-affinity state with respect to both agonists and antagonists. By comparison, α2 receptors may exist in multiple-affinity states reflecting the ability of the α2 binding-site protein to form a complex with additional membrane proteins that themselves are receptors for the physiological substrates guanosine 5'-triphosphate (GTP), Na+, Mg2+, and possibly Ca2+-calmodulin. Binding studies have also strongly indicated that α2 receptors in most, if not all, tissues are probably coupled in an inhibitory manner to adenylate cyclase, as has been demonstrated in platelets, adipocytes, and NG 108-15 cells. Nothing is known about the mechanisms of regulation of α1 receptors, although both up- and down-regulations of α1 receptor have been demonstrated. In this regard, the ability to label and study α1 receptors on cells in culture would be particularly useful. With regard to α2 receptors, the number of affinity states that exist and their role in terms of the kinetics of α2-receptor coupling to adenylate cyclase are still not clear.read more
Citations
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Journal ArticleDOI
Characterization of the selectivity, specificity and potency of medetomidine as an α2-adrenoceptor agonist
TL;DR: Based on results, medetomidine can be classified as a potent, selective and specific alpha 2-adrenoceptor agonist.
Journal ArticleDOI
Distributions of mRNAs for alpha-2 adrenergic receptor subtypes in rat brain: an in situ hybridization study.
TL;DR: The present study justifies the pharmacological subclassification ofalpha‐2 receptors by providing anatomical evidence for specific and selective cell groups in the rat central nervous system containing mRNA for three alpha‐2 receptor subtypes.
Journal ArticleDOI
Clonidine binds to imidazole binding sites as well as α2-adrenoceptors in the ventrolateral medulla
TL;DR: Describing binding sites labeled by [3H]p-aminoclonidine in bovine brain membranes prepared from the ventrolateral medulla found that these sites may mediate, in part, the hypotensive action of clonidine and other imidazole compounds in the ventral medulla.
Journal ArticleDOI
Stress and brain noradrenaline: a review.
Gary B. Glavin,Gary B. Glavin +1 more
TL;DR: The majority of experimental evidence supports a central role for brain noradrenaline in mediating the effects of stress and predisposing an organism to stress pathology as well as in producing a well-documented consequence of stress exposure-behavioral depression.
Journal ArticleDOI
Heterogeneity of alpha-2 adrenergic receptors.
TL;DR: The ability to pharmacologically define putative alpha-2 adrenergic receptor subtypes should promote the development of additional subtype selective drugs which will increase the understanding of adrenergic pharmacology and may provide new therapeutic approaches.
References
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Journal ArticleDOI
A study of the adrenotropic receptors
TL;DR: Experiments described in this paper indicate that although there are two kinds of adrenotropic receptors they cannot be classified simply as excitatory or inhibitory since each kind of receptor may have either action depending upon where it is found.
Journal ArticleDOI
Differentiation of receptor systems activated by sympathomimetic amines.
TL;DR: The classification of receptor systems which are activated by sympathomimetic amines has engaged the attention of many investigators as mentioned in this paper, who have suggested the convenient designations of alpha (α) and beta (β) to distinguish major differences in the responses elicited in various organ systems.
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