Excitatory and inhibitory local circuit input to the rat dorsal motor nucleus of the vagus originating from the nucleus tractus solitarius

• Published in: Brain research 2004-08, Vol.1017 (1), p.208-217
• Main Authors: Davis, Scott F, Derbenev, Andrei V, Williams, Kevin W, Glatzer, Nicholas R, Smith, Bret N
• Format: Article
• Language: English
• Subjects: Animals; Animals, Newborn; Biological and medical sciences; Brain Mapping; Central nervous system; Electric Stimulation - methods; Electrophysiology; Excitatory Postsynaptic Potentials - drug effects; Excitatory Postsynaptic Potentials - physiology; Excitatory Postsynaptic Potentials - radiation effects; Fundamental and applied biological sciences. Psychology; GABA; Glutamate photostimulation; Glutamates - pharmacology; Glutamic Acid - pharmacology; In Vitro Techniques; Male; Membrane Potentials - drug effects; Motor Neurons - drug effects; Motor Neurons - physiology; Motor Neurons - radiation effects; Neural Inhibition - drug effects; Neural Inhibition - physiology; Neural Inhibition - radiation effects; Neural Pathways - physiology; Patch-clamp; Patch-Clamp Techniques - methods; Photolysis; Rats; Rats, Sprague-Dawley; Reflex; Solitary Nucleus - physiology; Synaptic current; Vagus Nerve - physiology; Vertebrates: nervous system and sense organs
• ISSN: 0006-8993; 1872-6240
• DOI: 10.1016/j.brainres.2004.05.049

The nucleus tractus solitarius (NTS) and dorsal motor nucleus of the vagus nerve (DMV) constitute sensory and motor nuclei of the dorsal vagal complex, respectively. We used whole-cell patch-clamp recordings from DMV neurons in rat brain slices and three methods of stimulation (electrical, glutamate microdrop, glutamate photostimulation) to test the hypothesis that convergent excitatory and inhibitory inputs to DMV neurons originate from intact neurons in multiple NTS areas. Electrical stimulation of the NTS resulted in evoked excitatory and inhibitory postsynaptic currents (eEPSCs and eIPSCs) in DMV neurons. Stimulation of the dorsal NTS with glutamate microdrops, which selectively stimulates the soma and dendrites of intact neurons, resulted in 31% of DMV neurons receiving eEPSCs, 44% receiving eIPSCs, and 6% receiving convergent excitatory and inhibitory inputs. Glutamate photostimulation allowed selective activation of intact neurons in multiple, discrete areas of the NTS and resulted in 36% of DMV neurons receiving eEPSCs, 65% receiving eIPSCs and 20% receiving both inputs. Data obtained by stimulation of multiple NTS areas support the hypothesis that there are anatomically convergent inputs to DMV neurons originating from intact neurons within the NTS. These data support the hypothesis that there is transfer of convergent information from the NTS to the DMV, implying that significant sensory–motor processing occurs within the brainstem.