Alpha-adrenergic mRNA subtype expression in the human nasal turbinate.
OBJECTIVE
Alpha-adrenergic receptor (AR) agonist drugs (e.g., epinephrine) are commonly used for upper airway procedures, to shrink the mucosa, retard absorption of local anesthetic agents, and improve visualization by limiting hemorrhage. Decongestant therapy often also includes alphaAR agonist agents, however overuse of these drugs (e.g., oxymetazoline) can result in chronic rhinitis and rebound increases in nasal secretion. Since current decongestants stimulate alphaARs non-selectively, characterization of alphaAR subtype distribution in human airway (nasal turbinate) offers an opportunity to refine therapeutic targets while minimizing side-effects. We, therefore, investigated alphaAR subtype expression in human nasal turbinate within epithelial, duct, gland, and vessel cells using in situ hybridization.


METHODS
Since sensitive and specific anti-receptor antibodies and highly selective alphaAR subtype ligands are currently unavailable, in situ hybridization was performed on sections of three human nasal turbinate samples to identify distribution of alphaAR subtype mRNA. Subtype specific (35)S-labelled mRNA probes were incubated with nasal turbinate sections, and protected fragments remaining after RNase treatment analyzed by light and darkfield microscopy.


RESULTS
In non-vascular tissue alpha(1d) AR mRNA predominates, whereas notably the alpha(2c) is the only alphaAR subtype present in the sinusoids and arteriovenous anastamoses.


CONCLUSIONS
Combined with the current understanding that AR-mediated constriction of nasal sinusoids underpins decongestant therapies that minimize secretions and shrink tissues for airway procedures, these findings suggest that alpha(2c) AR subtypes provide a novel selective target for decongestant therapy in humans.
Stafford-Smith
Mark
M
Department of Anesthesiology, Duke University Medical Center, DUMC, Durham, NC 27710, USA. staff002@mc.duke.edu
Bartz
Raquel
R
Wilson
Katrina
K
Baraniuk
James N
JN
Schwinn
Debra A
DA
D005088:Exocrine Glands / Q000378:metabolism; D006801:Humans; D017403:In Situ Hybridization; D009297:Nasal Mucosa / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics*; D011942:Receptors, Adrenergic, alpha / Q000096:biosynthesis* / Q000235:genetics*; D013462:Sulfur Radioisotopes; D014420:Turbinates / Q000378:metabolism*
D012333:RNA, Messenger; D011942:Receptors, Adrenergic, alpha; D013462:Sulfur Radioisotopes