Abstract
This study was designed to determine whether smooth muscle α-actin mRNA and smooth muscle α-actin contractile protein elements were present within the renal medullary pericytes. Extraction of total RNA from microdissected outer medullary descending vasa recta allowed for the detection of smooth muscle α-actin mRNA expression using reverse transcription-polymerase chain reaction (RT-PCR). Expression of smooth muscle α-actin was specific to the descending vasa recta and not a result of tubular contamination because RT- PCR amplification of the vasopressin V2 receptor, which is a specific tubular marker, did not occur. To determine the exact cell type(s) that translate the mRNA into protein, we performed immunohistochemistry on the renal outer and inner medulla using a monoclonal smooth muscle α-actin antibody, whose specificity was determined by immunoblot analysis. Smooth muscle α-actin protein was found selectively within the pericytes surrounding the descending vasa recta from the outer and inner medullary tissue sections. This study demonstrates that the pericytes alone that surround the descending vasa recta within the outer and inner medulla contain smooth muscle α-actin mRNA and protein and are therefore the site of the contractile elements that could play a vasomodulatory role in the control of renal medullary blood flow and its distribution within the renal medulla.
Original language | English (US) |
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Pages (from-to) | R1742-R1748 |
Journal | American Journal of Physiology - Regulatory Integrative and Comparative Physiology |
Volume | 273 |
Issue number | 5 42-5 |
DOIs | |
State | Published - 1997 |
Externally published | Yes |
Keywords
- Descending vasa recta
- Immunohistochemistry
- Microdissection
- Renal medullary blood flow
- Reverse transcription-polymerase chain reaction
- Western blot analysis
ASJC Scopus subject areas
- Physiology
- Physiology (medical)