The effects of the protein kinase C (PKC) inhibitor 1-(5-isoquinolinesulphonyl)-2-methylpiperazine (H-7) on evoked synaptic potentials were investigated in the CA1 region of rat hippocampal slices by use of extracellular and intracellular recording techniques. 2. Extracellular recordings showed that superfusion with H-7 (10-100 microM) increased the amplitude of the population spike and the initial slope of the dendritic field e.p.s.p. H-7 also produced the appearance of multiple population spikes in the somatic region and in the dendritic field e.p.s.p. 3. H-7 (30 microM) induced the disappearance of intracellularly recorded inhibitory potentials elicited by orthodromic stimulation of CA1 pyramidal cells. At this concentration H-7 had no effect on resting membrane potential, input membrane resistance, and spike threshold. In voltage-clamped neurones H-7 blocked the antidromically evoked inhibitory currents and the spontaneous miniature inhibitory currents. 4. The hyperpolarizing effect of bath applied gamma-aminobutyric acid (GABA, 500 microM) or isoguvacine (30 microM) was not affected by 30 microM H-7. 5. Neither the PKC activity regulator sphingosine (10-40 microM) nor the H-7 analogue N-(2-guanidinoethyl)-5-isoquinolinesulphonamide (HA-1004, 20-50 microM) which is devoid of activity on PKC at these concentrations, affected the extracellularly recorded dendritic field e.p.s.p. or population spike. 6. It is concluded that the disinhibitory effect produced by H-7 is due to the block of a H-7-sensitive PKC which is involved in the spontaneous and evoked release of GABA.
The protein kinase C inhibitor 1-(5-isoquinolinesulphonyl)-2-methylpiperazine (H-7) disinhibits CA1 pyramidal cells in rat hippocampal slices / R. CORRADETTI; A.M. PUGLIESE; N. ROPERT. - In: BRITISH JOURNAL OF PHARMACOLOGY. - ISSN 0007-1188. - STAMPA. - 98(4):(1989), pp. 1376-1382.
The protein kinase C inhibitor 1-(5-isoquinolinesulphonyl)-2-methylpiperazine (H-7) disinhibits CA1 pyramidal cells in rat hippocampal slices
CORRADETTI, RENATO;PUGLIESE, ANNA MARIA;
1989
Abstract
The effects of the protein kinase C (PKC) inhibitor 1-(5-isoquinolinesulphonyl)-2-methylpiperazine (H-7) on evoked synaptic potentials were investigated in the CA1 region of rat hippocampal slices by use of extracellular and intracellular recording techniques. 2. Extracellular recordings showed that superfusion with H-7 (10-100 microM) increased the amplitude of the population spike and the initial slope of the dendritic field e.p.s.p. H-7 also produced the appearance of multiple population spikes in the somatic region and in the dendritic field e.p.s.p. 3. H-7 (30 microM) induced the disappearance of intracellularly recorded inhibitory potentials elicited by orthodromic stimulation of CA1 pyramidal cells. At this concentration H-7 had no effect on resting membrane potential, input membrane resistance, and spike threshold. In voltage-clamped neurones H-7 blocked the antidromically evoked inhibitory currents and the spontaneous miniature inhibitory currents. 4. The hyperpolarizing effect of bath applied gamma-aminobutyric acid (GABA, 500 microM) or isoguvacine (30 microM) was not affected by 30 microM H-7. 5. Neither the PKC activity regulator sphingosine (10-40 microM) nor the H-7 analogue N-(2-guanidinoethyl)-5-isoquinolinesulphonamide (HA-1004, 20-50 microM) which is devoid of activity on PKC at these concentrations, affected the extracellularly recorded dendritic field e.p.s.p. or population spike. 6. It is concluded that the disinhibitory effect produced by H-7 is due to the block of a H-7-sensitive PKC which is involved in the spontaneous and evoked release of GABA.File | Dimensione | Formato | |
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