α1-adrenergic receptors in human spinal cord:: specific localized expression of mRNA encoding α1-adrenergic receptor subtypes at four distinct levels

alpha(1)-Adrenergic receptors (alpha(1)ARs) are important in lower urinary tract syndromes such as benign prostatic hypertrophy and bladder irritability. Spinal cord alpha(1)ARs have been postulated to play a role in modulating these diseases, yet alpha(1)AR subtype (alpha(1a), alpha(1b), alpha(1d)) neuronal localization in human spinal cord has not been described. We therefore tested the hypothesis that or,AR subtype distribution varies according to specific spinal cord tract and level. In situ hybridization was performed to identify cell bodies containing alpha(1)AR subtype mRNA at four levels of human spinal cord (cervical enlargement, thoracic, lumbar, sacral). alpha(1)AR mRNA is present in ventral gray matter only (ventral > dorsal; sacral > lumbar = thoracic > cervical). Signaling cell bodies were detected in anterior horn motor neurons at all levels; dorsal nucleus of Clarke and intermediolateral columns in cervical enlargement, thoracic and lumbar spinal cord regions; and parasympathetic nucleus in sacral spinal cord. Although all three alpha(1)AR subtypes are present throughout human spinal cord, alpha(1d) mRNA predominates overall. If confirmed at a protein level, these findings may contribute to the development of new therapeutic strategies in the treatment of several human diseases. (C) 1999 Elsevier Science B.V. All rights reserved.