Axonal projections from the pontine pneumotaxic region to the nucleus raphe magnus in cats.
In 15 pentobarbital anesthetized and vagotomized cats, 60 non-respiratory units recorded from the medial parabrachial and Kölliker-Fuse nuclear complex (NPBM-KF), were found to be antidromically activated by electrical stimulation of the nucleus raphe magnus (NRM). Seven respiratory units (6 inspiratory, 1 expiratory), comprising 8.0% of the 87 respiratory units examined, were also antidromically activated by stimulation of the NRM. The antidromic latencies ranged from 0.4 to 2.5 ms (mean 1.2 ms). In 6 cats, following injection of WGA-HRP (wheat germ agglutinin-conjugated horseradish peroxidase) into the NRM, a number of retrogradely labelled neurons were observed mainly in the NPBM-KF complex, and some in subcoeruleus nucleus and adjacent tegmental field. These results demonstrate that predominantly non-respiratory and a portion of respiratory neurons in the rostral pons, especially in the NPBM-KF complex, send a monosynaptic axonal projection to the NRM. It is suggested that the NPBM-KF to NRM pathway could be, in part, involved in the control of respiration as well as nociception control.
Gang
S
S
Department of Physiology, Sapporo Medical College, Japan.
Mizuguchi
A
A
Aoki
M
M
D000818:Animals; D001369:Axons; D002415:Cats; D004594:Electrophysiology; D005260:Female; D006735:Horseradish Peroxidase; D008297:Male; D009434:Neural Pathways; D011149:Pons / Q000033:anatomy & histology* / Q000502:physiology; D011903:Raphe Nuclei / Q000033:anatomy & histology* / Q000502:physiology; D012119:Respiration / Q000502:physiology*; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D014909:Wheat Germ Agglutinins
D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate; D014909:Wheat Germ Agglutinins; D006735:Horseradish Peroxidase