These results show that HCN3 makes some contribution to excitability, particularly in medium-sized neurons, although it has no major influence on acute or neuropathic pain processing.
HCN2 modulates action potential firing rate in nociceptive neurons and plays a critical role in all modes of inflammatory and neuropathic pain, although the role of HCN3 in nociceptive excitability and pain is less studied.
Genetic deletion of HCN3 had no effect on acute thresholds to heat or mechanical stimuli in vivo and did not affect inflammatory pain measured with the formalin test.
Nerve-injured HCN3 knockout mice exhibited similar levels of mechanical allodynia and thermal hyperalgesia to wild-type mice but reduced mechanical hyperalgesia in response to a pinprick.
Pain sensitivity both acutely and following neuropathic injury was largely unaffected by HCN3 deletion, with the exception of a small decrease of mechanical hyperalgesia in response to a pinprick.
We previously demonstrated that defective development of urinary tract pacemaker cells (utPMCs) expressing hyperpolarization-activated cyclic nucleotide-gated channel 3 (HCN3) and the stem cell marker cKIT causes abnormal ureteric peristalsis and nonobstructive hydronephrosis.
Our cell-type selective transcriptome analyses of BGON in the rat 6-hydroxydopamine (6-OHDA) model of PD identified the ion channel HCN3 as a likely contributor to altered neuronal excitability.