Kv1.1/1.2 channels are downstream effectors of nitric oxide on synaptic GABA release to preautonomic neurons in the paraventricular nucleus

Qing Yang, S. R. Chen, D. P. Li, H. L. Pan

Research output: Contribution to journalArticle

32 Citations (Scopus)

Abstract

The paraventricular nucleus (PVN) of the hypothalamus is important for the neural regulation of cardiovascular function. Nitric oxide (NO) increases synaptic GABA release to presympathetic PVN neurons through the cyclic guanosine monophosphate (cGMP)/protein kinase G signaling pathway. However, the downstream signaling mechanisms underlying the effect of NO on synaptic GABA release remain unclear. In this study, whole-cell voltage-clamp recordings were performed on retrograde-labeled spinally projecting PVN neurons in rat brain slices. Bath application of the NO precursor l-arginine or the NO donor S-nitroso-N-acetylpenicillamine (SNAP) significantly increased the frequency of GABAergic miniature inhibitory postsynaptic currents (mIPSCs) in labeled PVN neurons. A specific antagonist of cyclic ADP ribose, 8-bromo-cyclic ADP ribose (8-Br-cADPR), had no significant effect on l-arginine-induced potentiation of mIPSCs. Surprisingly, blocking of voltage-gated potassium channels (Kv) with 4-aminopyridine or α-dendrotoxin eliminated the effect of l-arginine on mIPSCs in all labeled PVN neurons tested. The membrane permeable cGMP analog mimicked the effect of l-arginine on mIPSCs, and this effect was blocked by α-dendrotoxin. Furthermore, the specific Kv channel blocker for Kv1.1 (dendrotoxin-K) or Kv1.2 (tityustoxin-Kα) abolished the effect of l-arginine on mIPSCs in all neurons tested. SNAP failed to inhibit the firing activity of labeled PVN neurons in the presence of dendrotoxin-K, Kα. Additionally, the immunoreactivity of Kv1.1 and Kv1.2 subunits was colocalized extensively with synaptophysin in the PVN. These findings suggest that NO increases GABAergic input to PVN presympathetic neurons through a downstream mechanism involving the Kv1.1 and Kv1.2 channels at the nerve terminals.

Original languageEnglish (US)
Pages (from-to)315-327
Number of pages13
JournalNeuroscience
Volume149
Issue number2
DOIs
StatePublished - Oct 26 2007
Externally publishedYes

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Paraventricular Hypothalamic Nucleus
gamma-Aminobutyric Acid
Nitric Oxide
Inhibitory Postsynaptic Potentials
Neurons
Arginine
S-Nitroso-N-Acetylpenicillamine
Kv1.2 Potassium Channel
Guanylate Kinases
Cyclic ADP-Ribose
Voltage-Gated Potassium Channels
Cyclic GMP-Dependent Protein Kinases
4-Aminopyridine
Synaptophysin
Nitric Oxide Donors
Cyclic GMP
Baths
Hypothalamus
Membranes
Brain

Keywords

  • autonomic regulation
  • nitric oxide
  • potassium channels
  • presynaptic regulation
  • sympathetic nervous system
  • synaptic transmission

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Kv1.1/1.2 channels are downstream effectors of nitric oxide on synaptic GABA release to preautonomic neurons in the paraventricular nucleus. / Yang, Qing; Chen, S. R.; Li, D. P.; Pan, H. L.

In: Neuroscience, Vol. 149, No. 2, 26.10.2007, p. 315-327.

Research output: Contribution to journalArticle

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abstract = "The paraventricular nucleus (PVN) of the hypothalamus is important for the neural regulation of cardiovascular function. Nitric oxide (NO) increases synaptic GABA release to presympathetic PVN neurons through the cyclic guanosine monophosphate (cGMP)/protein kinase G signaling pathway. However, the downstream signaling mechanisms underlying the effect of NO on synaptic GABA release remain unclear. In this study, whole-cell voltage-clamp recordings were performed on retrograde-labeled spinally projecting PVN neurons in rat brain slices. Bath application of the NO precursor l-arginine or the NO donor S-nitroso-N-acetylpenicillamine (SNAP) significantly increased the frequency of GABAergic miniature inhibitory postsynaptic currents (mIPSCs) in labeled PVN neurons. A specific antagonist of cyclic ADP ribose, 8-bromo-cyclic ADP ribose (8-Br-cADPR), had no significant effect on l-arginine-induced potentiation of mIPSCs. Surprisingly, blocking of voltage-gated potassium channels (Kv) with 4-aminopyridine or α-dendrotoxin eliminated the effect of l-arginine on mIPSCs in all labeled PVN neurons tested. The membrane permeable cGMP analog mimicked the effect of l-arginine on mIPSCs, and this effect was blocked by α-dendrotoxin. Furthermore, the specific Kv channel blocker for Kv1.1 (dendrotoxin-K) or Kv1.2 (tityustoxin-Kα) abolished the effect of l-arginine on mIPSCs in all neurons tested. SNAP failed to inhibit the firing activity of labeled PVN neurons in the presence of dendrotoxin-K, Kα. Additionally, the immunoreactivity of Kv1.1 and Kv1.2 subunits was colocalized extensively with synaptophysin in the PVN. These findings suggest that NO increases GABAergic input to PVN presympathetic neurons through a downstream mechanism involving the Kv1.1 and Kv1.2 channels at the nerve terminals.",
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N2 - The paraventricular nucleus (PVN) of the hypothalamus is important for the neural regulation of cardiovascular function. Nitric oxide (NO) increases synaptic GABA release to presympathetic PVN neurons through the cyclic guanosine monophosphate (cGMP)/protein kinase G signaling pathway. However, the downstream signaling mechanisms underlying the effect of NO on synaptic GABA release remain unclear. In this study, whole-cell voltage-clamp recordings were performed on retrograde-labeled spinally projecting PVN neurons in rat brain slices. Bath application of the NO precursor l-arginine or the NO donor S-nitroso-N-acetylpenicillamine (SNAP) significantly increased the frequency of GABAergic miniature inhibitory postsynaptic currents (mIPSCs) in labeled PVN neurons. A specific antagonist of cyclic ADP ribose, 8-bromo-cyclic ADP ribose (8-Br-cADPR), had no significant effect on l-arginine-induced potentiation of mIPSCs. Surprisingly, blocking of voltage-gated potassium channels (Kv) with 4-aminopyridine or α-dendrotoxin eliminated the effect of l-arginine on mIPSCs in all labeled PVN neurons tested. The membrane permeable cGMP analog mimicked the effect of l-arginine on mIPSCs, and this effect was blocked by α-dendrotoxin. Furthermore, the specific Kv channel blocker for Kv1.1 (dendrotoxin-K) or Kv1.2 (tityustoxin-Kα) abolished the effect of l-arginine on mIPSCs in all neurons tested. SNAP failed to inhibit the firing activity of labeled PVN neurons in the presence of dendrotoxin-K, Kα. Additionally, the immunoreactivity of Kv1.1 and Kv1.2 subunits was colocalized extensively with synaptophysin in the PVN. These findings suggest that NO increases GABAergic input to PVN presympathetic neurons through a downstream mechanism involving the Kv1.1 and Kv1.2 channels at the nerve terminals.

AB - The paraventricular nucleus (PVN) of the hypothalamus is important for the neural regulation of cardiovascular function. Nitric oxide (NO) increases synaptic GABA release to presympathetic PVN neurons through the cyclic guanosine monophosphate (cGMP)/protein kinase G signaling pathway. However, the downstream signaling mechanisms underlying the effect of NO on synaptic GABA release remain unclear. In this study, whole-cell voltage-clamp recordings were performed on retrograde-labeled spinally projecting PVN neurons in rat brain slices. Bath application of the NO precursor l-arginine or the NO donor S-nitroso-N-acetylpenicillamine (SNAP) significantly increased the frequency of GABAergic miniature inhibitory postsynaptic currents (mIPSCs) in labeled PVN neurons. A specific antagonist of cyclic ADP ribose, 8-bromo-cyclic ADP ribose (8-Br-cADPR), had no significant effect on l-arginine-induced potentiation of mIPSCs. Surprisingly, blocking of voltage-gated potassium channels (Kv) with 4-aminopyridine or α-dendrotoxin eliminated the effect of l-arginine on mIPSCs in all labeled PVN neurons tested. The membrane permeable cGMP analog mimicked the effect of l-arginine on mIPSCs, and this effect was blocked by α-dendrotoxin. Furthermore, the specific Kv channel blocker for Kv1.1 (dendrotoxin-K) or Kv1.2 (tityustoxin-Kα) abolished the effect of l-arginine on mIPSCs in all neurons tested. SNAP failed to inhibit the firing activity of labeled PVN neurons in the presence of dendrotoxin-K, Kα. Additionally, the immunoreactivity of Kv1.1 and Kv1.2 subunits was colocalized extensively with synaptophysin in the PVN. These findings suggest that NO increases GABAergic input to PVN presympathetic neurons through a downstream mechanism involving the Kv1.1 and Kv1.2 channels at the nerve terminals.

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