Substance P receptor-like immunoreactive neurons in the caudal spinal trigeminal nucleus send axons to the gelatinosus thalamic nucleus in the rat.
By means of substance P receptor (SPR) immunofluorescence histochemistry combined with Fluoro-Gold (FG) fluorescent retrograde labeling, SPR-like immunoreactive neurons in the caudal spinal trigeminal nucleus of the rat were observed to send their axons to the gelatinosus thalamic nucleus with a clear ipsilateral dominance. FG/SPR double-labeled neurons were distributed mainly in the ventral part of lamina I at the rostral level of the caudal spinal trigeminal nucleus. The percentages of FG/SPR-LI neurons in the total number of SPR-LI neurons and FG-labeled neurons are 10.5% and 31.1%, respectively. The present results suggest that trigemino-gelatinosus thalamic projection neurons with SPR-LI in the caudal spinal trigeminal nucleus might receive SP-containing, nociceptive primary afferent fibers from the orofacial region and transmit nociception to the gelatinosus thalamic nucleus.
Li
Y Q
YQ
Department of Anatomy and K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, People's Republic of China. deptanat@mail.fmmu.edu.cn
D000818:Animals; D001370:Axonal Transport; D001369:Axons / Q000502:physiology / Q000648:ultrastructure; D005456:Fluorescent Dyes; D007839:Functional Laterality; D008297:Male; D009474:Neurons / Q000166:cytology*; D051381:Rats; D017208:Rats, Wistar; D018040:Receptors, Neurokinin-1 / Q000032:analysis*; D013266:Stilbamidines; D013376:Substantia Gelatinosa / Q000033:anatomy & histology / Q000502:physiology; D013787:Thalamic Nuclei / Q000033:anatomy & histology* / Q000502:physiology*; D014279:Trigeminal Nucleus, Spinal / Q000033:anatomy & histology* / Q000502:physiology*
C049774:2-hydroxy-4,4'-diamidinostilbene, methanesulfonate salt; D005456:Fluorescent Dyes; D018040:Receptors, Neurokinin-1; D013266:Stilbamidines