Abstract
Growing evidence suggests a possible link between hyperpolarization-activated
cyclic nucleotide-gated nonselective cation (HCN) channels and depression. In a
recent study published in Molecular Psychiatry, we first
demonstrate that Ih (the membrane current mediated
by HCN channels) and HCN1 protein expression were increased in dorsal, but not
in ventral, CA1 region following chronic, but not acute stress. This
upregulation of Ih was restricted to the perisomatic
region of CA1 neurons and contributed to a reduction of neuronal excitability. A
reduction of HCN1 protein expression in dorsal CA1 region before the onset of
chronic unpredictable stress-induced depression was sufficient to provide
resilient effects to chronic unpredictable stress. Furthermore, in vivo block of
the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) pumps, a manipulation
known to increase intracellular calcium levels and upregulate
Ih, produced anxiogenic-like behavior and an
increase in Ih, similar to that observed in chronic
unpredictable stress model of depression. Here, we share our view on (1) how the
function and expression of HCN1 channels are changed in the brain in a
subcellular region-specific manner during the development of depression and (2)
how a reduction of HCN1 protein expression provides resilience to chronic
stress.
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