Activation of P sub(2)-purino-, alpha sub(1)-adreno and H sub(1)-histamine receptors triggers cytoplasmic calcium signalling in cerebellar Purkinje neurons
The cytoplasmic calcium concentration ([Ca super(2+)] sub(i)) was measured from Purkinje neurons in acutely prepared cerebellar slices. Neurons were loaded with calcium indicator Fura-2 by 40-min slice incubation in Tyrode solution containing 5 mu M Fura-2/AM and 0.02% pluronic-F127. Bath applicatio...
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Veröffentlicht in: | Neuroscience 1996-06, Vol.73 (3), p.643-647 |
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Sprache: | eng |
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Zusammenfassung: | The cytoplasmic calcium concentration ([Ca super(2+)] sub(i)) was measured from Purkinje neurons in acutely prepared cerebellar slices. Neurons were loaded with calcium indicator Fura-2 by 40-min slice incubation in Tyrode solution containing 5 mu M Fura-2/AM and 0.02% pluronic-F127. Bath applications of ATP (100 mu M), epinephrine (10 mu M) and histamine (100 mu M) triggered a transient increase of [Ca super(2+)] sub(i) in Purkinje neurons. ATP-induced [Ca super(2+)] sub(i) elevation in Purkinje neurons was mimicked by ADP, but not AMP or adenosine pointing to the involvement of P sub(2Y) metabotropic purinoreceptors. Epinephrine-triggered [Ca super(2+)] sub(i) responses were blocked by the selective alpha sub(1)-antagonist prazosin and were mimicked by the alpha sub(1)-adrenoreceptor agonist phenylephrine, and were not affected by beta - and alpha sub(2)-adrenoreceptor agonists (isoproterenol and clonidine) and antagonists (propranolol and yohimbine). Histamine-induced [Ca super(2+)] sub(i) responses demonstrated specific sensitivity to selective H sub(1) antagonist chlorpheniramine, and were not sensitive to H sub(2) and H sub(3) histamine receptors modulators. The [Ca super(2+)] sub(i) responses to all three agonists persisted in Ca super(2+)-free extracellular media and were blocked by slice preincubation with thapsigargin (500 nM). We conclude that cerebellar Purkinje neurons are endowed with metabotropic P sub(2Y) purinoreceptors, alpha sub(1)-adrenoreceptors, and H sub(1) histamine receptors which mediate the generation of intracellular [Ca super(2+)] sub(i) signals via activation of Ca super(2+) release from inositol-1,4,5-trisphosphate-sensitive intracellular stores. |
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ISSN: | 0306-4522 |