Chemical stimulation of the nucleus locus coeruleus: cardiovascular responses and baroreflex modification.
Microinjection of glutamate (Glu, 2.5 nmol) or homocysteic acid (HA, 0.1-0.5 nmol) into the nucleus locus coeruleus (LC) decreased both blood pressure and heart rate. These microinjections also produced a facilitatory or occlusive effect on depressor and bradycardiac responses evoked by electrical stimulation of the aortic depressor nerve (ADN). Destruction of the nucleus tractus solitarius (NTS), which totally eliminated ADN-evoked responses, had no effect on the cardiovascular responses evoked by LC stimulation. These results suggest that the neuronal populations that contribute to the LC-induced cardiovascular responses overlap at least partly with the baroreflex substrate other than the NTS.
Murase
S
S
Department of Physiology, Mie University School of Medicine, Japan.
Takayama
M
M
Nosaka
S
S
D000818:Animals; D001011:Aorta / Q000294:innervation; D001794:Blood Pressure / Q000502:physiology; D002320:Cardiovascular Physiological Phenomena; D003714:Denervation; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D006339:Heart Rate / Q000502:physiology; D006710:Homocysteine / Q000031:analogs & derivatives / Q000494:pharmacology; D008125:Locus Coeruleus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D008526:Medulla Oblongata / Q000502:physiology; D008845:Microinjections; D009424:Nervous System Physiological Phenomena; D011311:Pressoreceptors / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000502:physiology*; D013268:Stimulation, Chemical
D005971:Glutamates; D006710:Homocysteine; C007956:homocysteic acid; D018698:Glutamic Acid