Locus coeruleus projections to the dorsal motor vagus nucleus in the rat.
The origin of the noradrenergic innervation of the preganglionic autonomic nuclei in the medulla oblongata and spinal cord is still controversial. In this investigation descending connections of the locus coeruleus to the dorsal motor vagus nucleus in the rat are studied with Phaseolus vulgaris leucoagglutinin and horseradish peroxidase as neuroanatomical tracers. Locus coeruleus projections in the motor vagus nucleus are found in the medial part at rostral levels and in the lateral part at intermediate levels of this nucleus. The terminal labeling in the lateral intermediate part of the vagus nucleus appears in an area where possibly preganglionic parasympathetic cardiac neurons are located, suggesting that the locus coeruleus might be involved in regulation of cardiovascular functions. After small iontophoretic injections of horseradish peroxidase in the motor vagus nucleus, retrogradely labeled cells are found in the ventral part of the locus coeruleus and occasionally in the dorsal part of the nucleus. The results show that the locus coeruleus-dorsal motor vagus nucleus pathway may participate in the inhibition of the cardiac preganglionic neurons in the dorsal motor vagus nucleus by the hypothalamic paraventricular nucleus.
Ter Horst
G J
GJ
Department of Neurobiology and Oral Physiology, University of Groningen, The Netherlands.
Toes
G J
GJ
Van Willigen
J D
JD
D000818:Animals; D001339:Autonomic Fibers, Preganglionic / Q000502:physiology / Q000648:ultrastructure*; D001931:Brain Mapping; D004525:Efferent Pathways / Q000033:anatomy & histology; D006735:Horseradish Peroxidase; D008125:Locus Coeruleus / Q000033:anatomy & histology* / Q000502:physiology; D008297:Male; D009046:Motor Neurons / Q000502:physiology / Q000648:ultrastructure; D010286:Paraventricular Hypothalamic Nucleus / Q000033:anatomy & histology / Q000502:physiology; D010835:Phytohemagglutinins; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000033:anatomy & histology* / Q000502:physiology; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis; D014630:Vagus Nerve / Q000033:anatomy & histology* / Q000502:physiology
D010835:Phytohemagglutinins; C100156:leukoagglutinins, plants; D006735:Horseradish Peroxidase; D014446:Tyrosine 3-Monooxygenase