RGD Reference Report - beta2-Adrenergic receptor stimulation in vivo induces apoptosis in the rat heart and soleus muscle. - Rat Genome Database

RGD Reference Report - beta2-Adrenergic receptor stimulation in vivo induces apoptosis in the rat heart and soleus muscle. - Rat Genome Database

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beta2-Adrenergic receptor stimulation in vivo induces apoptosis in the rat heart and soleus muscle.
Authors:	Burniston, JG Tan, LB Goldspink, DF
Citation:	Burniston JG, etal., J Appl Physiol. 2005 Apr;98(4):1379-86. Epub 2004 Dec 10.
RGD ID:	1598751
Pubmed:	PMID:15591297 (View Abstract at PubMed)
DOI:	DOI:10.1152/japplphysiol.00642.2004 (Journal Full-text)
High doses of the beta2-adrenergic receptor (AR) agonist clenbuterol can induce necrotic myocyte death in the heart and slow-twitch skeletal muscle of the rat. However, it is not known whether this agent can also induce myocyte apoptosis and whether this would occur at a lower dose than previously reported for myocyte necrosis. Male Wistar rats were given single subcutaneous injections of clenbuterol. Immunohistochemistry was used to detect myocyte-specific apoptosis (detected on cryosections via a caspase 3 antibody and confirmed with annexin V, single-strand DNA labeling, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling). Myocyte apoptosis was first detected at 2 h and peaked 4 h after clenbuterol administration. The lowest dose of clenbuterol to induce cardiomyocyte apoptosis was 1 microg/kg, with peak apoptosis (0.35 +/- 0.05%; P < 0.05) occurring in response to 5 mg/kg. In the soleus, peak apoptosis (5.8 +/- 2%; P < 0.05) was induced by the lower dose of 10 microg/kg. Cardiomyocyte apoptosis was detected throughout the ventricles, atria, and papillary muscles. However, this damage was most abundant in the left ventricular subendocardium at a point 1.6 mm, that is, approximately one-quarter of the way, from the apex toward the base. beta-AR antagonism (involving propranolol, bisoprolol, or ICI 118551) or reserpine was used to show that clenbuterol-induced myocardial apoptosis was mediated through neuromodulation of the sympathetic system and the cardiomyocyte beta1-AR, whereas in the soleus direct stimulation of the myocyte beta2-AR was involved. These data show that, when administered in vivo, beta2-AR stimulation by clenbuterol is detrimental to cardiac and skeletal muscles even at low doses, by inducing apoptosis through beta1- and beta2-AR, respectively.

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Term	Qualifier	Evidence	With	Reference	Notes	Source	Original Reference(s)
positive regulation of apoptotic process		IMP		1598751		RGD

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Genes (Rattus norvegicus)

Adrb2 (adrenoceptor beta 2)

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