TRPC channels are not required for graded persistent activity in entorhinal cortex neurons

Area of Science:

• Neuroscience
• Molecular Biology
• Computational Neuroscience

Background:

• Adaptive behavior relies on short-term memory, often involving sustained neuronal firing.
• Persistent firing in medial entorhinal cortex (mEC) layer V (LV) neurons is linked to cholinergic muscarinic receptors and a calcium-activated nonselective cation current (I_CAN).

Purpose of the Study:

• To investigate the molecular identity of the I_CAN responsible for persistent firing in mEC LV neurons.
• To determine if canonical transient receptor potential (TRPC) channels are involved in muscarinic-dependent persistent neuronal activity.

Main Methods:

• Utilized two distinct lines of TRPC channel knockout mice: one lacking TRPC1, TRPC4, and TRPC5; the other lacking all seven TRPC family members.
• Recorded neuronal activity in layer V neurons of the medial entorhinal cortex in these knockout models.

Main Results:

• Persistent firing in mEC LV neurons was observed to be unchanged in TRPC channel-depleted mice.
• The absence of TRPC1, TRPC4, TRPC5, or all TRPC channels did not affect muscarinic-dependent persistent activity.

Conclusions:

• Canonical transient receptor potential (TRPC) channels are not essential for generating muscarinic-dependent persistent firing in mEC LV neurons.
• This study rules out TRPC channels as the molecular basis for the I_CAN mediating this form of short-term memory crucial for adaptive behavior.