Altered pain responses in mice lacking alpha 1E subunit of the voltage-dependent Ca2+ channel

Proc Natl Acad Sci U S A. 2000 May 23;97(11):6132-7. doi: 10.1073/pnas.100124197.

Abstract

alpha(1) subunit of the voltage-dependent Ca(2+) channel is essential for channel function and determines the functional specificity of various channel types. alpha(1E) subunit was originally identified as a neuron-specific one, but the physiological function of the Ca(2+) channel containing this subunit (alpha(1E) Ca(2+) channel) was not clear compared with other types of Ca(2+) channels because of the limited availability of specific blockers. To clarify the physiological roles of the alpha(1E) Ca(2+) channel, we have generated alpha(1E) mutant (alpha(1E)-/-) mice by gene targeting. The lacZ gene was inserted in-frame and used as a marker for alpha(1E) subunit expression. alpha(1E)-/- mice showed reduced spontaneous locomotor activities and signs of timidness, but other general behaviors were apparently normal. As involvement of alpha(1E) in pain transmission was suggested by localization analyses with 5-bromo-4-chloro-3-indolyl beta-d-galactopyranoside staining, we conducted several pain-related behavioral tests using the mutant mice. Although alpha(1E)+/- and alpha(1E)-/- mice exhibited normal pain behaviors against acute mechanical, thermal, and chemical stimuli, they both showed reduced responses to somatic inflammatory pain. alpha(1E)+/- mice showed reduced response to visceral inflammatory pain, whereas alpha(1E)-/- mice showed apparently normal response compared with that of wild-type mice. Furthermore, alpha(1E)-/- mice that had been presensitized with a visceral noxious conditioning stimulus showed increased responses to a somatic inflammatory pain, in marked contrast with the wild-type mice in which long-lasting effects of descending antinociceptive pathway were predominant. These results suggest that the alpha(1E) Ca(2 +) channel controls pain behaviors by both spinal and supraspinal mechanisms.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetic Acid / toxicity
  • Animals
  • Anxiety / genetics
  • Calcium / physiology*
  • Calcium Channels, R-Type / deficiency
  • Calcium Channels, R-Type / genetics
  • Calcium Channels, R-Type / physiology*
  • Exploratory Behavior
  • Fear
  • Formaldehyde / toxicity
  • Gene Expression
  • Inflammation / chemically induced
  • Inflammation / physiopathology
  • Ion Transport
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Nociceptors / physiopathology
  • Pain / physiopathology*
  • Pain Insensitivity, Congenital / etiology*
  • Pain Insensitivity, Congenital / genetics
  • Pain Insensitivity, Congenital / physiopathology
  • Pain Measurement
  • Peritonitis / chemically induced
  • Peritonitis / physiopathology
  • Recombinant Fusion Proteins / physiology
  • Reflex, Startle / genetics
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • Calcium Channels, R-Type
  • Recombinant Fusion Proteins
  • Formaldehyde
  • Acetic Acid
  • Calcium