NO Differentially Regulates Neurotransmission to Premotor Cardiac Vagal Neurons in the Nucleus Ambiguus
| Autor: | Christopher Gorini, Evguenia Bouairi, Zheng Gui Huang, Olga Dergacheva, Xin Wang, Harriet Kamendi, David Mendelowitz |
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| Rok vydání: | 2006 |
| Předmět: |
Nitroprusside
Autonomic Fibers Preganglionic In Vitro Techniques Neurotransmission Biology Arginine Nitric Oxide Inhibitory postsynaptic potential Rats Sprague-Dawley Glutamatergic Receptors Glycine Slice preparation Receptors GABA Internal Medicine Animals Nitric Oxide Donors Glycine receptor Nucleus ambiguus Medulla Oblongata Heart Vagus Nerve Rats Receptors Neurotransmitter Anesthesia Excitatory postsynaptic potential GABAergic Neuroscience Central Nervous System Agents |
| Zdroj: | Hypertension. 48:1137-1142 |
| ISSN: | 1524-4563 0194-911X |
| DOI: | 10.1161/01.hyp.0000246493.00385.94 |
| Popis: | NO is involved in the neural control of heart rate, and NO synthase expressing neurons and terminals have been localized in the nucleus ambiguus where parasympathetic cardiac vagal preganglionic neurons are located; however, little is known about the mechanisms by which NO alters the activity of premotor cardiac vagal neurons. This study examines whether the NO donor sodium nitroprusside ([SNP] 100 μmol/L) and precursor, l -arginine (10 mmol/L), modulate excitatory and inhibitory synaptic neurotransmission to cardiac vagal preganglionic neurons. Glutamatergic, GABAergic, and glycinergic activity to cardiac vagal neurons was examined using whole-cell patch-clamp recordings in an in vitro brain slice preparation in rats. Both SNP, as well as l -arginine, increased the frequency of GABAergic neurotransmission to cardiac vagal preganglionic neurons but decreased the amplitude of GABAergic inhibitory postsynaptic currents. In contrast, both l -arginine and SNP inhibited the frequency of glutamatergic and glycinergic synaptic events in cardiac vagal preganglionic neurons. SNP and l -arginine also decreased glycinergic inhibitory postsynaptic current amplitude, and this response persisted in the presence of tetrodotoxin. Inclusion of the NO synthase inhibitor 7-nitroindazole (100 μmol/L) prevented the l -arginine–evoked responses. These results demonstrate that NO differentially regulates excitatory and inhibitory neurotransmission, facilitating GABAergic and diminishing glutamatergic and glycinergic neurotransmission to cardiac vagal neurons. |
| Databáze: | OpenAIRE |
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