Submandibular gland acinar cells express multiple alpha1-adrenoceptor subtypes

J Pharmacol Exp Ther. 2004 Oct;311(1):364-72. doi: 10.1124/jpet.104.066399. Epub 2004 Jul 20.


We evaluated an acinar cell line (SMG-C10) cloned from rat submandibular glands as a possible model for alpha(1)-adrenoceptor regulation of submandibular function. alpha(1)-Adrenoceptors are subdivided into three subtypes called alpha(1A), alpha(1B), and alpha(1D), which can be distinguished from one another by their differential affinity values for subtype-selective alpha(1)-adrenoceptor antagonists. Thus, alpha(1)-adrenoceptor subtypes in SMG-C10 cells were characterized with reverse transcription-polymerase chain reaction (RT-PCR) and [(3)H]prazosin binding in side-by-side experiments with native submandibular glands. RT-PCR identified mRNAs for alpha(1A)-, alpha(1B)-, and alpha(1D)-adrenoceptors in SMG-C10 cells and submandibular glands. The inhibition of [(3)H]prazosin binding by 5-methylurapidil (alpha(1A)-selective) was biphasic and fit best to a two-site binding model with 40 +/- 8% high (K(iH))- and 60 +/- 10% low (K(iL))-affinity binding sites in SMG-C10 cells, and 76% high- and 24% low-affinity binding sites in submandibular glands. Respective K(iH) and K(iL) values for 5-methylurapidil were 1.9 +/- 0.4 and 100 +/- 30 nM in SMG-C10 cells and 3.2 +/- 0.8 and 170 +/- 20 nM in submandibular glands. BMY-7378 [8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-8-azaspiro[4.5]decane-7,9-dione dihydrochloride (alpha(1D)-selective)] bound with low affinity in SMG-C10 cells and submandibular glands with K(i) values of 81 +/- 20 and 110 +/- 20 nM, respectively. Chloroethylclondine, an irreversible alkylating agent selective for alpha(1B) adrenoceptors, reduced the density of [(3)H]prazosin binding sites by 42 and 26% in SMG-C10 and submandibular membranes, respectively. Thus, SMG-C10 cells and submandibular glands are similar in expressing receptor protein for alpha(1A)- and alpha(1B)-adrenoceptor subtypes, establishing SMG-C10 cells as a potential model for alpha(1)-adrenoceptor-mediated secretion.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenergic alpha-Antagonists / pharmacology
  • Animals
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cells, Cultured
  • Clonidine / analogs & derivatives*
  • Clonidine / pharmacology
  • Male
  • Prazosin / pharmacology
  • RNA, Messenger / metabolism
  • Radioligand Assay
  • Rats
  • Rats, Sprague-Dawley
  • Receptors, Adrenergic, alpha-1 / genetics
  • Receptors, Adrenergic, alpha-1 / metabolism*
  • Receptors, Adrenergic, alpha-2 / genetics
  • Receptors, Adrenergic, alpha-2 / metabolism*
  • Submandibular Gland / cytology
  • Submandibular Gland / drug effects
  • Submandibular Gland / metabolism*
  • Tritium


  • Adrenergic alpha-Antagonists
  • RNA, Messenger
  • Receptors, Adrenergic, alpha-1
  • Receptors, Adrenergic, alpha-2
  • Tritium
  • chlorethylclonidine
  • Clonidine
  • Prazosin