Deletion of Cacna1c (CaV1.2) in D1-expressing cells elicits divergent sex-specific effects on aversive and spatial memories

Abstract

Dopamine signaling is critical for cognitive and emotional regulation and is implicated in multiple neuropsychiatric disorders. One downstream effector of dopamine is the L-type calcium channel CaV1.2, encoded by the risk gene CACNA1C. Genome-wide association studies have consistently linked CACNA1C single nucleotide polymorphisms to schizophrenia, bipolar disorder, and related conditions. We previously showed that homozygous deletion of Cacna1c in dopamine receptor 1 (D1)-expressing cells enhances remote (30 days post-training) contextual fear memory in male mice. Here, we extend these findings by examining sex- and gene dosage-specific behavioral consequences of Cacna1c loss in D1 cells. We find that D1-Cacna1c deletion produces a sex- and gene dosage-dependent effect on fear memory. In males, homozygous loss of D1-Cacna1c heightens remote contextual fear at 30-days post-training, replicating prior findings, whereas partial loss had no effect. Cue-associated fear memory remained unaffected across genotypes. In contrast, females exhibited heightened contextual fear with both heterozygous and homozygous D1-Cacna1c loss at 24-hrs, 7-days, and 30-days post-training, indicating increased sensitivity to contextual aversive learning. Cue-associated fear memory was higher at 24-hrs but normalized at later time points in females. In the Water Y-maze, males with heterozygous or homozygous D1-Cacna1c loss showed impaired spatial memory at 7-days post-training, whereas females were unaffected. D1-Cacna1c deletion reduced locomotor activity selectively in females during the initial 5-mins of a 60-min session, with no genotype effects in males. Social interaction and anxiety-like behavior were unchanged across groups. Together, these findings highlight the interplay between dopamine receptor signaling and calcium channel function in shaping sex-dependent aspects of memory.