Modulation of ATP-induced currents by zinc in acutely isolated hypothalamic neurons of the rat.

1. Whole-cell patch-clamp and fast perfusion were used to study the effects of zinc on adenosine 5'-triphosphate (ATP)-induced responses of histaminergic neurons. 2.

Expression and function of P2X purinoceptors in rat histaminergic neurons.

(1) The pharmacology of ATP responses and the expression pattern of seven known subunits of the P2X receptor were investigated in individual histaminergic neurons of the tuberomamillary nucleus (TM). (2) ATP (3-1000 micro M) evoked fast non-desensitizing inward currents in TM neurons. 2-methylthioATP (2MeSATP) displayed the same efficacy but a lower potency, EC(50)s 84 micro M versus 48 micro M, when compared with ATP.

GABA(A) receptor heterogeneity in histaminergic neurons.

Histaminergic neurons of the tuberomamillary nucleus display pacemaker properties; their firing rate is regulated according to behavioural state by gabaergic inhibition. Whole-cell recordings and single-cell RT-PCR from acutely isolated rat tuberomamillary neurons were used to characterize GABA -evoked currents and to correlate them with the expression pattern of 12 GABAA receptor subunits. We report differences in sensitivity to GABA and zinc as well as in the modulation of IPSC-decay times by zolpidem in histaminergic neurons expressing gamma-subunits at different levels.

Mechanisms of GABA(A) receptor blockade by millimolar concentrations of furosemide in isolated rat Purkinje cells.

The action of diuretic furosemide on the GABA(A) receptor was studied in acutely isolated Purkinje cells using the whole-cell recording and fast application system. Furosemide blocked stationary component of GABA-activated currents in a concentration-dependent manner with IC(50) value > 5 mM at -70 mV. The inhibition was rapid in the onset, fully reversible and did not require drug pre-perfusion.