Cardiac afferents to the nucleus of the tractus solitarius: A WGA-HRP study in the rat.
Central distribution of the sensory fibers of the heart was investigated in the rat by the use of transganglionic transport of horseradish peroxidase (HRP). After the left intercostal thoracotomy was done under deep anesthesia and artificial respiration, wheat germ agglutinin-conjugated HRP (WGA-HRP) was injected into the left and right ventricular walls and the apex of the heart. HRP-labeled fibers were observed to be distributed to the dorsomedial portion of the medulla oblongata through the vagal nerve. The labeled fibers were present in various subnuclei of the nucleus of the tractus solitarius (NTS) bilaterally at the level of +0.36 to -1.74 mm to the obex. However, the most conspicuous feature in the present study was that the labeled fibers were exclusively confined to the medial, ventrolateral and commissural NTS with some distribution to the dorsolateral NTS. Although the labeling in the medial and ventrolateral NTS was observed to extend rostrocaudally, it was of interest that the labeling in the medial NTS was divided into the ventral and dorsal parts at the level around the obex. Accumulation of the labeled fibers in the commissural NTS was found at the level caudal to the obex and these fibers were traced to the caudal portion of its subnucleus with a gradual decrease in number. This pattern of distribution of cardiac afferents in the NTS was considered to be peculiar to the rat, because it was quite different from that reported previously in the cat.
Xie
Q
Q
Department of Anatomy, Faculty of Medicine, Kagawa Medical University, 1750-1 Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793.
Itoh
M
M
Miyamoto
K
K
Li
L
L
Takeuchi
Y
Y
D000344:Afferent Pathways / Q000033:anatomy & histology*; D000818:Animals; D001933:Brain Stem / Q000033:anatomy & histology; D002415:Cats; D006325:Heart Atria / Q000294:innervation; D006329:Heart Conduction System / Q000033:anatomy & histology*; D006346:Heart Septum / Q000294:innervation; D006352:Heart Ventricles / Q000294:innervation; D008297:Male; D008526:Medulla Oblongata / Q000033:anatomy & histology; D008845:Microinjections; D015335:Molecular Probes; D009412:Nerve Fibers / Q000648:ultrastructure; D009475:Neurons, Afferent / Q000648:ultrastructure; D051381:Rats; D017208:Rats, Wistar; D017552:Solitary Nucleus / Q000033:anatomy & histology* / Q000648:ultrastructure; D013908:Thoracotomy; D014630:Vagus Nerve / Q000033:anatomy & histology; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate / Q000008:administration & dosage
D015335:Molecular Probes; D018998:Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate