Factors contributing to pressure overload-induced immediate early gene expression in adult rat hearts in vivo.
We determined the contributions of angiotensin II type 1 receptor (AT(1)) stimulation, adrenergic stimulation, and autonomic activation to pressure overload-induced c-fos expression in the adult rat heart in vivo. c-fos expression was increased in pressure-overloaded hearts created by aortic banding compared with sham-operated rats (458 +/- 100% vs. sham, P < 0.05). GR-138950, a selective AT(1) antagonist, did not blunt this expression (banding vs. banding + GR-138950: 458 +/- 100% vs. 500 +/- 125%, not significant). Atropine and hexamethonium partially decreased c-fos expression (banding vs. banding + atropine/hexamethonium: 700 +/- 67% vs. 400 +/- 67%, P < 0.05). Phentolamine had no significant effect on c-fos expression; however, propranolol inhibited the expression (banding vs. banding + propranolol: 492 +/- 108% vs. 154 +/- 15%, P < 0.05). The inhibition by propranolol was independent of the decreases in heart rate. Thus factors contributing to pressure overload-induced c-fos expression in adult rat hearts in vivo are different from those in neonatal myocytes in vitro undergoing stretch.
Department of Medicine, College of Physicians & Surgeons, Columbia University, New York, New York 10032, USA. ogino@grape.med.tottori-u.ac.jp
K
K
Ogino
B
B
Cai
A
A
Gu
T
T
Kohmoto
N
N
Yamamoto
D
D
Burkhoff
D000818:Animals; D015870:Gene Expression; D017781:Genes, Immediate-Early / Q000235:genetics*; D016762:Genes, fos / Q000235:genetics; D009206:Myocardium / Q000166:cytology*; D011312:Pressure; D051381:Rats; D017208:Rats, Wistar; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011941:Receptors, Adrenergic / Q000187:drug effects / Q000502:physiology; D011945:Receptors, Angiotensin / Q000502:physiology
D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011941:Receptors, Adrenergic; D011945:Receptors, Angiotensin