Atrial natriuretic peptide receptor upregulation in the rat inner ear.
The purpose of this study was to further examine whether fluid homeostasis in the endolymphatic system could be regulated by a locally effective paracrine system involving atrial natriuretic peptides (ANPs) and their receptors. We assessed the biologic activity of the 3 ANP receptors (ANP-A, ANP-B, ANP-C) in the rat inner ear by measuring receptor upregulation after inner ear administration of ANPs. After appropriate anesthesia, female Lewis rats were injected with ANP via the round window. The animals were sacrificed 24 hours later, and RNA was isolated for reverse transcription-polymerase chain reaction (RT-PCR). Electrophoresis of RT-PCR products showed the presence of all 3 ANP receptor genes in both injected and control animals. Gene expression was significantly higher 24 hours after injection. These findings demonstrate that ANP receptors in the inner ear can be upregulated after injection of ANPs.
Dornhoffer
John L
JL
Department of Otolaryngology-Head and Neck Surgery, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA.
Danner
Christopher
C
Zhou
Lin
L
Li
Shulin
S
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000008:administration & dosage*; D003720:Densitometry; D007758:Ear, Inner / Q000378:metabolism / Q000502:physiology*; D004586:Electrophoresis; D004712:Endolymphatic Sac / Q000378:metabolism / Q000502:physiology; D005260:Female; D005990:Glycerol / Q000008:administration & dosage; D006706:Homeostasis; D008575:Meniere Disease / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D012313:RNA / Q000302:isolation & purification; D051381:Rats; D011917:Rats, Inbred Lew; D017461:Receptors, Atrial Natriuretic Factor / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D015854:Up-Regulation
D012313:RNA; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor; D005990:Glycerol