Plasticity in ion channel expression underlies variation in hearing during reproductive cycles.

Sensory plasticity related to reproductive state, hormonal profiles, and experience is widespread among vertebrates, including humans. Improvements in audio-vocal coupling that heighten the detection of conspecifics are part of the reproductive strategy of many nonmammalian vertebrates. Although seasonal changes in hearing are known, molecular mechanisms determining this form of adult sensory plasticity remain elusive. Among both nonmammals and mammals, large-conductance, calcium-activated potassium (BK) channels underlie a primary outward current having a predominant influence on frequency tuning in auditory hair cells. We now report an example from fish showing that increased BK channel abundance can improve an individual's ability to hear vocalizations during the breeding season. Pharmacological manipulations targeting BK channels, together with measures of BK transcript abundance, can explain the seasonal enhancement of auditory hair cell sensitivity to the frequency content of calls. Plasticity in ion channel expression is a simple, evolutionarily labile solution for sculpting sensory bandwidth to maximize the detection of conspecific signals during reproductive cycles.