HIGHLIGHTS
- Cancer borealis stomach muscles are sensitive to temperature and pH.
- Warming or alkalizing hyperpolarizes fibers and reduces synaptic response amplitude.
- qRT-PCR detects K2P gene transcripts CbKCNK1 and CbKCNK2 in muscles.
- CbKCNK1 and CbKCNK2 are candidates for the temperature and pH-dependent conductances.
SUMMARY
Marine crustaceans such as the crab Cancer borealis experience fluctuations in temperature and pH, yet their stomatogastric neuromuscular system must remain functional for feeding. We examined 16 of ∼40 stomach muscle pairs and found that warming consistently hyperpolarized muscle fibers (∼10 mV per 10°C) and reduced excitatory junctional potentials and currents. Muscle responses were also strongly influenced by extracellular pH, with an optimal range between pH 6.7 and 8.8; outside this window, abnormal activity emerged. Voltage-clamp analysis of gastric muscle gm5b revealed a temperature- and pH-sensitive conductance with a reversal potential near the potassium equilibrium potential and insensitivity to tetraethylammonium and barium, arguing against classical voltage-gated potassium channels. Quantitative RT-PCR detected expression of two putative two-pore domain potassium (K2P) channels in these muscles. Together, these results suggest that muscle excitability in C. borealis is shaped by temperature- and pH-sensitive potassium currents consistent with contributions from K2P channels.
Jacquerie K., Poghosyan A., Schulz D. & Marder E., 2026. Temperature and pH-dependent potassium currents of muscles of the stomatogastric nervous system of the crab, Cancer borealis. iScience: 115244. doi: 10.1016/j.isci.2026.115244. Article.
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