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Pterostilbene (PTER), a natural dimethylated analog of resveratrol, has been demonstrated to produce anti-neoplastic or neuroprotective actions. However, how and whether this compound can entail any perturbations on ionic currents in electrically excitable cells remains unknown. In whole-cell current recordings, addition of PTER decreased the amplitude of macroscopic <i>I</i>_h during long-lasting hyperpolarization in GH₃ cells in a concentration-dependent manner, with an effective IC₅₀ value of 0.84 &#956;M. Its presence also shifted the activation curve of <i>I</i>_h along the voltage axis to a more hyperpolarized potential, by 11 mV. PTER at a concentration greater than 10 &#956;M could also suppress <span style="font-variant: small-caps;">l</span>-type Ca²⁺ and transient outward K⁺ currents in GH₃ cells. With the addition of PTER, <i>I</i>_K(Ca) amplitude was increased, with an EC₅₀ value of 2.23 &#956;M. This increase in <i>I</i>_K(Ca) amplitude was attenuated by further addition of verruculogen, but not by tolbutamide or TRAM-39. Neither atropine nor nicotine, in the continued presence of PTER, modified the PTER-stimulated <i>I</i>_K(Ca). PTER (10 &#956;M) slightly suppressed the amplitude of <span style="font-variant: small-caps;">l</span>-type Ca²⁺ current and transient outward K⁺ current. The presence of PTER (3 &#956;M) was also effective at increasing the open-state probability of large-conductance Ca²⁺-activated K⁺ (BK_Ca) channels identified in hippocampal mHippoE-14 neurons; however, its inability to alter single-channel conductance was detected. Our study highlights evidence to show that PTER has the propensity to perturb ionic currents (e.g., <i>I</i>_h and <i>I</i>_K(Ca)), thereby influencing the functional activities of neurons, and neuroendocrine or endocrine cells.