The Yin and Yang of L-Type calcium channels: age-related roles in learning and memory

Critch, Tristian (2022) The Yin and Yang of L-Type calcium channels: age-related roles in learning and memory. Masters thesis, Memorial University of Newfoundland.

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Abstract

L-Type calcium channels (LTCCs) are intricately involved in the process of learning and memory. In the young population, the LTCCs are beneficial to the learning process and help facilitate the learning process. As we age, our ability to recall and form new memories deteriorates. We hypothesize that there is a paradoxical shift in the role of LTCCs in learning and memory during ageing. Specifically, there is an increase in the number of or hyperfunction of the LTCCs present in the cell as we age, increasing calcium entering the cell. This causes divergence from calcium homeostasis, thus being a mechanism contributing to a decline in one’s cognitive ability. In this work, we have set out to systematically investigate the potential effects of blocking LTCCs using a calcium channel antagonist, nimodipine, at various ages. Using an odour associative learning task and a spontaneous location recall test, we find that LTCC blockade impairs performance of young rats while rescuing performance of aged rats, demonstrating the shift in their role during ageing. Further, nimodipine infusions into the CA1 region of the hippocampus and the piriform cortex block learning as well as prevent c-Fos activation in the piriform cortex, showing the critical role of LTCCs in synaptic plasticity in young rats. These findings further elucidate our current understanding of the roles that LTCCs play when it comes to memory formation, function, and duration.

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