Phenotype-specific expression of T-type calcium channels in neurons of the major pelvic ganglion of the adult male rat

J Physiol. 1995 Dec 1;489 ( Pt 2)(Pt 2):363-75. doi: 10.1113/jphysiol.1995.sp021057.


1. Neurons from the major pelvic ganglia (MPG) of adult male rats were enzymatically dissociated and the neurochemical phenotype and Ca2+ current properties examined. 2. Neurons were divided into two subpopulations based on the presence or absence of low threshold T-type Ca2+ channels. The subpopulation of neurons expressing T-type Ca2+ channels was characterized by a mean diameter of 34 microns, a mean membrane capacitance (Cm) of 72 pF, tyrosine hydroxylase immunoreactivity (TH-IR), a lack of NADPH diaphorase (NADPHd) reactivity and a high degree of alpha 2-adrenoceptor-mediated Ca2+ current inhibition (60%). 3. The subpopulation of neurons without overt T-type Ca2+ channels had a mean diameter of 23 microns, a mean Cm of 30 pF, a lack of TH-IR and a moderate degree of alpha 2-adrenoceptor-mediated Ca2+ current inhibition (27%). About 50% of this subpopulation stained positively for NADPHd. 4. The contribution of high threshold N-type Ca2+ channels (60-70%), as determined from omega-conotoxin GVIA inhibition, and L-type Ca2+ channels (< 10%), as determined from nifedipine inhibition, to the whole-cell Ca2+ current was similar for both subpopulations of neurons. 5. These data indicate that the MPG contain at least two subpopulations of postganglionic neurons, i.e. adrenergic and non-adrenergic, with distinct electrophysiological and neurochemical properties. Furthermore, we propose that the presence or absence of T-type Ca2+ channels provides an electrophysiological means of identifying adrenergic and non-adrenergic phenotype, respectively, in neurons of the male rat MPG.

Publication types

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

MeSH terms

  • Animals
  • Calcium Channels / genetics*
  • Cell Count
  • Gene Expression / genetics
  • Hypogastric Plexus / physiology*
  • Male
  • NADPH Dehydrogenase / metabolism
  • Neurons / physiology*
  • Nifedipine / pharmacology
  • Patch-Clamp Techniques
  • Phenotype
  • Rats
  • Time Factors
  • Tyrosine 3-Monooxygenase / metabolism


  • Calcium Channels
  • Tyrosine 3-Monooxygenase
  • NADPH Dehydrogenase
  • Nifedipine