Molecular basis of R-type calcium channels in central amygdala neurons of the mouse.
R-type Ca2+ channels play a critical role in coupling excitability to dendritic Ca2+ influx and neuronal secretion. Unlike other types of voltage-sensitive Ca2+ channels (L, N, P/Q, and T type), the molecular basis for the R-type Ca2+ channel is still unclear, thereby limiting further detailed analyses of R-type Ca2+ channel physiology. The prevailing hypothesis is that alpha(1E) (Ca(V)2.3) gene encodes for R-type Ca2+ channels, but the dearth of critical evidence has rendered this hypothesis controversial. Here we generated alpha1E-deficient mice (alpha1E-/-) and examined the status of voltage-sensitive Ca2+ currents in central amygdala (CeA) neurons that exhibit abundant alpha1E expression and R-type Ca2+ currents. The majority of R-type currents in CeA neurons were eliminated in alpha1E-/- mice whereas other Ca2+ channel types were unaffected. These data clearly indicate that the expression of alpha1E gene underlies R-type Ca2+ channels in CeA neurons. Furthermore, the alpha1E-/- sign mice exhibited signs of enhanced fear as evidenced by their vigorous escaping behavior and aversion to open-field conditions. These latter findings imply a possible role of alpha1E-based R-type Ca2+ currents in amygdala physiology associated with fear.
Lee
Seung-Chan
SC
National Creative Research Initiatives Center for Calcium and Learning, Korea Institute of Science and Technology, Seoul 136-791, Korea.
Choi
Sukwoo
S
Lee
Taehoon
T
Kim
Hyung-Lae
HL
Chin
Hemin
H
Shin
Hee-Sup
HS
D000679:Amygdala / Q000166:cytology; D000818:Animals; D001007:Anxiety / Q000209:etiology; D015220:Calcium Channels / Q000235:genetics / Q000502:physiology*; D020908:Calcium Channels, R-Type / Q000235:genetics / Q000502:physiology*; D027682:Cation Transport Proteins; D004924:Escape Reaction; D005239:Fear; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D051381:Rats
C498916:Cacna1e protein, mouse; C498917:Cacna1e protein, rat; D015220:Calcium Channels; D020908:Calcium Channels, R-Type; D027682:Cation Transport Proteins