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Beta 3-adrenoceptors in the cardiovascular system
M Berlan1, J Galitzky, J L Montastruc
1Laboratoire de Pharmacologie Médicale et Clinique, Inserm U 317, Faculté de Médecine, Toulouse, France.
Fundamental & Clinical Pharmacology
|January 1, 1995
Summary
The beta 3-adrenoceptor, a newly identified receptor, shows potential cardiovascular effects, particularly vasodilation in dogs. Its presence and function in humans remain unclear, requiring further investigation.
Area of Science:
- Pharmacology
- Cardiovascular Physiology
- Adrenoceptor Research
Background:
- The beta 3-adrenoceptor is a recently identified receptor found in various mammalian tissues.
- Its role in the cardiovascular system is less understood compared to beta 1 and beta 2-adrenoceptors.
- Few studies have investigated the presence and function of beta 3-adrenoceptors in cardiovascular tissues.
Purpose of the Study:
- To review available data on the beta 3-adrenoceptor in the cardiovascular system.
- To explore the effects of beta 3-adrenoceptor agonists in different species.
- To determine the potential physiological relevance of vascular beta 3-adrenoceptors.
Main Methods:
- In vitro studies using rat carotid artery fragments.
- In vivo studies in dogs to assess cardiovascular responses.
- Review of existing pharmacological and molecular data.
Main Results:
- Beta 3-adrenoceptor agonists induced relaxation in rat carotid artery fragments.
- In dogs, these agonists caused vasodilation and increased heart rate (baroreflex-mediated).
- Vasodilation was prominent in cutaneous and adipose tissue vessels, with unclear mechanisms.
- Higher catecholamine doses were needed for vascular beta 3-adrenoceptor activation compared to beta 1/beta 2.
- Cardiovascular effects in humans were attributed to beta 1/beta 2, not beta 3-adrenoceptors.
Conclusions:
- Evidence suggests the presence of vascular (not cardiac) beta 3-adrenoceptors in dogs.
- The existence and cardiac role of beta 3-adrenoceptors in humans and other species require further resolution.
- The physiological significance of vascular beta 3-adrenoceptors remains to be elucidated.