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Keywords:

  • α1-Adrenoceptor subtype mRNA;
  • human vas deferens;
  • RNase protection assay;
  • in situ hybridization
  • 1
    This study was intended to quantify the amounts of the α1-adrenoceptor subtype mRNAs in human vas deferens, and demonstrate the receptor subtype responsible for the vas contraction.
  • 2
    The RNase protection assay showed that the mean total amount of α1a mRNA was 7.4±2.2 pg/5 μg of poly (A)+ RNA (97.0% of the total α1 mRNA) in the epididymal portion (E-vas) and 4.9±0.8 pg/5 μg of poly (A)+ RNA (96.3% of the total) in the pelvic portion (P-vas). The E-vas showed a tendency to have a greater α1a mRNA abundance than the P-vas (P=0.11). The α1b and α1d mRNAs were absent or of extremely low abundance.
  • 3
    By an in situ hybridization, the α1a and α1d mRNAs were recognized in the smooth muscle cells of the E-vas and the P-vas, and the distribution pattern the same in both tissues. The α1b mRNA positive site was scarcely detectable in both vas portions.
  • 4
    In a functional study, l-phenylephrine produced concentration-dependent contraction in the E-vas (Emax=2.24±0.70 g; pD2=5.32±0.09) and the P-vas (Emax=2.46±0.46 g; pD2=5.07±0.12). KMD-3213, a novel α1A-adrenoceptor-selective antagonist, caused parallel rightward shifts of the concentration–response curves for l-phenylephrine. Apparent pKB values were 9.90±0.16 for the E-vas and 9.71±0.17 for the P-vas. There was no significant difference in Emax, pD2 or pKB estimates between the two portions.
  • 5
    We have found that α1a mRNA is predominant in the human vas deferens, and confirmed that contraction of this organ is mediated by the α1A-adrenoceptor.

British Journal of Pharmacology (1997) 122, 1009–1014; doi:10.1038/sj.bjp.0701485