Aging alters voltage-gated calcium channels in prefrontal cortex pyramidal neurons in the HIV brain

We assessed firing and voltage-gated Ca²⁺ influx in medial prefrontal cortex (mPFC) pyramidal neurons from older (12 months old) HIV-1 transgenic (Tg) rats. We found that neurons from older Tg rats showed increased firing compared to non-Tg rats, but Ca²⁺ spikes were unchanged. However, stronger excitatory stimulation was needed to evoke Ca²⁺ spikes, which was associated with reduced mPFC Ca_v1.2 L-type Ca²⁺ channel (L-channel) protein. In contrast, L-channel protein was unaltered in younger (6–7 weeks old) Tg rats, which we previously found had enhanced neuronal Ca²⁺ influx. These studies demonstrate that aging alters HIV-induced Ca²⁺ channel dysfunction that affects mPFC activity.