Esophagocardiac convergence onto thoracic spinal neurons: comparison of cervical and thoracic esophagus.
The aim of this study was to characterize thoracic spinal neurons receiving convergent inputs from the esophagus, heart and somatic receptive fields. Extracellular potentials of single T3-T4 spinal neurons were recorded in pentobarbital anesthetized male rats. Thoracic and cervical esophageal distensions (TED, CED) were produced by water inflation of a latex balloon. A catheter was placed in the pericardial sac to administer bradykinin or a mixture of algogenic chemicals. 96/311 (31%) neurons responded to both TED and intrapericardial chemicals (IC) and 48/177 (27%) neurons responded to both CED and IC. Long-lasting excitatory responses were more frequently encountered (P<0.05) in esophagocardiac spinal neurons responding to TED (T-ECSNs, 62/91) than in neurons responding to CED (C-ECSNs, 23/47). Ninety-one percent of T-ECSNs and 98% of C-ECSNs had somatic fields on chest, axilla and upper back areas. Esophagocardiac convergence on thoracic spinal neurons provided a spinal mechanism that might mediate viscerovisceral nociception and reflexes.
Qin
Chao
C
Department of Physiology, University of Oklahoma Health Sciences Center, P.O. Box 26901, Oklahoma City, OK 73190, USA. chao-quin@ouhsc.edu
Chandler
Margaret J
MJ
Foreman
Robert D
RD
D000818:Animals; D004558:Electric Stimulation; D004947:Esophagus / Q000294:innervation* / Q000502:physiology*; D006321:Heart / Q000294:innervation* / Q000502:physiology*; D008297:Male; D009474:Neurons / Q000502:physiology*; D009475:Neurons, Afferent / Q000502:physiology; D010146:Pain / Q000139:chemically induced; D010812:Physical Stimulation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*