Presynaptic receptors may reduce transmitter release with different mechanisms. Both the alpha 2-agonist, clonidine and the Y2-agonist, neuropeptide Y fragment 13-36 (NPY 13-36), induce a concentration-dependent inhibition of the 4-aminopyridine (4-AP)-evoked [3H]noradrenaline ([3H]NA) release from hypothalamic synaptosomes. Changes in alpha 2- and Y2-modulation of noradrenaline (NA) release were observed by lowering the calcium influx with the use of omega-conotoxin (omega-CgTx), a calcium-channel blocking agent. In these experimental conditions, clonidine was less active, whereas NPY 13-36 preserved its efficacy. It therefore seems possible that presynaptic alpha 2-adrenoceptors can primarily inhibit NA release by reducing calcium influx via voltage-sensitive calcium channels (VSCC), while Y2-receptors may inhibit the intracellular release process with a mechanism independent of the calcium entry.

Martire, M., Pistritto, G., Mores, N., Agnati, L., Fuxe, K., Presynaptic A2-adrenoceptors and neuropeptide Y Y2 receptors inhibit [3H]noradrenaline release from rat hypothalamic synaptosomes via different mechanisms, <<NEUROSCIENCE LETTERS>>, 1995; 188 (1): 9-12 [http://hdl.handle.net/10807/9169]

Presynaptic A2-adrenoceptors and neuropeptide Y Y2 receptors inhibit [3H]noradrenaline release from rat hypothalamic synaptosomes via different mechanisms

Martire, Maria;Mores, Nadia;
1995

Abstract

Presynaptic receptors may reduce transmitter release with different mechanisms. Both the alpha 2-agonist, clonidine and the Y2-agonist, neuropeptide Y fragment 13-36 (NPY 13-36), induce a concentration-dependent inhibition of the 4-aminopyridine (4-AP)-evoked [3H]noradrenaline ([3H]NA) release from hypothalamic synaptosomes. Changes in alpha 2- and Y2-modulation of noradrenaline (NA) release were observed by lowering the calcium influx with the use of omega-conotoxin (omega-CgTx), a calcium-channel blocking agent. In these experimental conditions, clonidine was less active, whereas NPY 13-36 preserved its efficacy. It therefore seems possible that presynaptic alpha 2-adrenoceptors can primarily inhibit NA release by reducing calcium influx via voltage-sensitive calcium channels (VSCC), while Y2-receptors may inhibit the intracellular release process with a mechanism independent of the calcium entry.
1995
Inglese
Martire, M., Pistritto, G., Mores, N., Agnati, L., Fuxe, K., Presynaptic A2-adrenoceptors and neuropeptide Y Y2 receptors inhibit [3H]noradrenaline release from rat hypothalamic synaptosomes via different mechanisms, <<NEUROSCIENCE LETTERS>>, 1995; 188 (1): 9-12 [http://hdl.handle.net/10807/9169]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10807/9169
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