Related Experiment Video
Updated: Sep 11, 2026

Presynaptic Dopamine Dynamics in Striatal Brain Slices with Fast-scan Cyclic Voltammetry
Published on: January 12, 2012
Nitric oxide inhibits the dopamine-induced K+ current via guanylate cyclase in Aplysia neurons
M Sawada1, M Ichinose, G B Stefano
1Department of Physiology, Shimane Medical University, Izumo, Japan.
Abstract:
Nitric oxide (NO) is produced by the enzyme nitric oxide synthase (NOS) and has been implicated in inter- and intracellular communication in the nervous system. The present study was undertaken to assess the effects of sodium nitroprusside (SNP) and hydroxylamine (HOA), NO donors, on a dopamine (DA)-induced K+ current in identified Aplysia neurons using voltage-clamp and pressure ejection techniques. Bath-applied SNP (10-25 microM) reduced the DA-induced K+ current without affecting the resting membrane conductance and holding current. The DA-induced K+ current also was inhibited by the focal application of 200 microM HOA to the neuron somata. The DA-induced K+ current suppressing effects of SNP and HOA are completely reversible. Pretreatment with 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ; 1 microM), a specific inhibitor of NO-stimulated guanylate cyclase, and hemoglobin (50 microM), a nitric oxide scavenger, decreased the SNP-induced inhibition of the DA-induced current. In contrast, intracellular injection of 1 mM guanosine 3',5'-cyclic monophosphate (cGMP) or bath-applied 3-isobutyl-1-methylxanthine (IBMX; 50 microM), a non-specific phosphodiesterase inhibitor, inhibited the DA-induced current, mimicking the effect of the NO donors. These results demonstrate that SNP and HOA inhibit the DA-induced K+ current and that the mechanism of NO inhibition of the DA-induced current involves cGMP-dependent protein kinase.
Related Concept Videos
G-Protein Gated Ion Channels
Sensory organs,...
Nitric Oxide Signaling Pathway
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Neurochemical Transmission: Sites of Drug Action
Adrenergic Neurons: Neurotransmission
Synthesis: Catecholamine synthesis requires tyrosine, which is taken...
Neuromuscular Junction And Blockade

