Recent Advances in Ionic Mechanisms in Pituitary Cells: Implications for Electrophysiological and Electropharmacological Research

Pituitary cells are specialized cells located within the pituitary gland, a small, pea-sized gland situated at the base of the brain. Through the use of cellular electrophysiological techniques, the electrical properties of these cells have been progressively revealed. This review paper aims to introduce the ion currents that are known to be functionally expressed in pituitary cells. These currents include voltage-gated Na+ current (INa), erg-mediated K+ current (IK(erg)), M-type K+ current (IK(M)), hyperpolarization-activated cation current (Ih), and large-conductance Ca2+-activated K+ (BKCa) channel. The biophysical characteristics of the respective ion current were described. Additionally, we also provide explanations for the effect of various drugs or compounds on each of these currents. GH3-cell exposure to GV-58 can increase the magnitude of INa with concurrent raise in the inactivation time constant of the current. The presence of esaxerenone, an antagonist of aldosterone receptor, directly suppress the magnitude of peak and late INa. Risperidone, an atypical antipsychotic agent, is effective at suppressing IK(erg) amplitude directly, and di(2-ethylhexyl)-phthalate suppressed IK(erg). Solifenacin and kynurenic acid can interact with KM channel to stimulate IK(M), while carisbamate and cannabidiol inhibit Ih activated by sustained hyperpolarization. Moreover, either the presence of either rufinamide or QO-40 can enhance the activity of single BKCa channels. To sum it up, alterations in ion currents within native pituitary cells or pituitary tumor cells can influence their functional activity, particularly in processes like stimulus-secretion coupling. The effects of small-molecule modulators, as demonstrated here, bear significance in clinical, therapeutic, and toxicological contexts.