Like extinction, latent inhibition of conditioned fear in mice is blocked by systemic inhibition of L-type voltage-gated calcium channels.
Having recently shown that extinction of conditioned fear depends on L-type voltage-gated calcium channels (LVGCCs), we have been seeking other protocols that require this unusual induction mechanism. We tested latent inhibition (LI) of fear, because LI resembles extinction except that cue exposures precede, rather than follow, cue-shock pairing. Systemic injections of two LVGCC inhibitors, nifedipine and diltiazem, before pre-exposure blocked LI completely with no evidence of state-dependent learning. The results indicate that extinction and LI share a common molecular requirement and may support the notion that LI, like extinction, is a form of inhibitory learning.
Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute and Neuropsychiatric Institute, University of California, Los Angeles, Los Angeles, California 90095-1761, USA. mbarad@mednet.ucla.edu
Mark
M
Barad
Ashley M
AM
Blouin
Chris K
CK
Cain
D000704:Analysis of Variance; D000818:Animals; D001245:Association Learning / Q000187:drug effects / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020746:Calcium Channels, L-Type / Q000187:drug effects / Q000502:physiology*; D003214:Conditioning, Classical / Q000187:drug effects* / Q000502:physiology; D003463:Cues; D004110:Diltiazem / Q000494:pharmacology; D005108:Extinction, Psychological / Q000502:physiology; D005239:Fear / Q000187:drug effects* / Q000502:physiology; D007266:Inhibition, Psychological; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology*; D009543:Nifedipine / Q000494:pharmacology
D002121:Calcium Channel Blockers; D020746:Calcium Channels, L-Type; D004110:Diltiazem; D009543:Nifedipine