Back to Search
Start Over
Functional expression of angiotensin II receptors in type-I cells of the rat carotid body.
- Source :
- Pflügers Archiv: European Journal of Physiology; Jan2001, Vol. 441 Issue 4, p474-480, 7p
- Publication Year :
- 2001
-
Abstract
- Angiotensin II increases afferent discharge from the carotid body in vitro. We hypothesized that angiotensin II receptors (AT receptors) are expressed functionally in the type-I cell of the carotid body. Cytosolic free [Ca<superscript>2+</superscript>] ([Ca<superscript>2+</superscript>]<subscript>i</subscript>) in type-I cells freshly dissociated from rat carotid bodies was measured spectrofluorimetrically. Angiotensin II (10–100 nM) concentration-dependently increased [Ca<superscript>2+</superscript>]<subscript>i</subscript> in type-I cells. The [Ca<superscript>2+</superscript>]<subscript>i</subscript> response was blocked by pretreatment with losartan (1 µM), an AT<subscript>1</subscript> receptor antagonist, but not by blockade of AT<subscript>2</subscript> receptors with PD-123319 (1 µM). Moreover, the gene expression of AT<subscript>1</subscript> receptors was assessed by the reverse transcriptase polymerase chain reaction and gene transcripts of both AT<subscript>1a</subscript> and AT<subscript>1b</subscript> receptors were detected in the carotid body. In addition, immunohistochemical study revealed that AT<subscript>1</subscript> immunoreactivity was localized in lobules of type-I cells in the carotid body. Taken together, these results suggest that type-I cells in the rat carotid body express functional angiotensin II receptors. The binding of angiotensin II to the AT<subscript>1</subscript> receptors increases [Ca<superscript>2+</superscript>]<subscript>i</subscript>, a key step of the intracellular signalling cascade following the activation of the receptors. It is concluded that angiotensin II modulates carotid body chemoreceptor function directly via AT<subscript>1</subscript> receptors in the type-I cell. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00316768
- Volume :
- 441
- Issue :
- 4
- Database :
- Complementary Index
- Journal :
- Pflügers Archiv: European Journal of Physiology
- Publication Type :
- Academic Journal
- Accession number :
- 16131221
- Full Text :
- https://doi.org/10.1007/s004240000445