Neurons of nucleus of the solitary tract synchronize the EEG and elevate cerebral blood flow via a novel medullary area.
In anesthetized spinalized rat, electrical stimulation of the nucleus tractus solitarius (NTS) synchronizes the EEG by increasing the power of 4-6-Hz waves (>100%; P<0.01), and elevates cerebral blood flow (rCBF) by 18+/-5% (P<0.05). The coordinated response appears within seconds, is global, reversible, graded, evoked from the commissural sub-nucleus, and replicated by L-glutamate. The responses are markedly reduced by bilateral lesions or muscimol microinjections restricted to a region of ventral medullary reticular formation, the medullary cerebral vasodilator area (MCVA), a region from which stimulation elicits identical responses and mediates the comparable responses to hypoxic/ischemic excitation of sympathoexcitatory neurons of rostral ventrolateral medulla (RVLM). We conclude that: (a) excitation of intrinsic neurons of commissural NTS synchronizes the EEG and coordinately elevates rCBF; (b) the responses are mediated by excitation of neurons in MCVA; (c) the MCVA may be a common final pathway mediating cerebrovascular and EEG responses from multiple areas of CNS; and (d) the NTS-MCVA pathway may be a part of the anatomical substrate for behaviors, including slow-wave sleep and seizure suppression evoked by stimulation of visceral afferents terminating in NTS.
Golanov
E V
EV
Department of Neurology and Neuroscience, Division of Neurobiology, Weill Medical College of Cornell University, 411 E. 69th Street, New York, NY 10021, USA. egolano@mail.med.cornell.edu
Reis
D J
DJ
D000818:Animals; D001933:Brain Stem / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology*; D004558:Electric Stimulation; D004569:Electroencephalography / Q000187:drug effects; D018698:Glutamic Acid / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D008526:Medulla Oblongata / Q000098:blood supply / Q000502:physiology*; D008845:Microinjections; D009474:Neurons / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017552:Solitary Nucleus / Q000187:drug effects / Q000502:physiology*
D018698:Glutamic Acid