Chemical activation of cardiac receptors affects activity of superficial and deeper T3-T4 spinal neurons in rats

Chao Qin, Margaret J. Chandler, Kenneth Miller, Robert D. Foreman

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

The purposes of this study were to examine responses of superficial (depth <300 μm) and deeper thoracic spinal neurons to chemical stimulation of cardiac afferents and effects of descending influences on these neurons. Extracellular potentials of single T3-T4 neurons were recorded in pentobarbital anesthetized, paralyzed and ventilated male rats. A catheter was placed in the pericardial sac to administer 0.2 ml of a mixture of algogenic chemicals that contained adenosine (10-3 M), bradykinin, histamine, serotonin, prostaglandin E2 (10-5 M). Fifteen of 55 (27%) superficial neurons responsive to intrapericardial chemicals were compared to 80/169 (47%) deeper neurons. All 15 superficial neurons that responded to cardiac afferents were excited (E), whereas 66 deeper neurons were excited, ten were inhibited and four showed excitation-inhibition. Spontaneous activity of superficial neurons with short-lasting excitatory responses was significantly lower than that of deeper neurons (P<0.05). Somatic receptive fields on chest, axilla, arm and upper back areas were found for 77/95 (81%) neurons that responded to intrapericardial chemicals. The proportion of somatic field properties and their sizes in superficial neurons were similar to deeper neurons. After cervical spinal transection, both spontaneous activity and responses to chemical stimulation of cardiac afferents significantly increased in six out of six neurons excited by intrapericardial injections. Results showed that chemical stimulation of cardiac afferents excited superficial T3-T4 spinal neurons, whereas deeper neurons exhibited multiple patterns of responses. Some characteristics of subgroups of superficial neurons were quantitatively different from deeper neurons. Thoracic spinal neurons processing cardiac nociceptive information were under tonic descending inhibition.

Original languageEnglish
Pages (from-to)77-85
Number of pages9
JournalBrain Research
Volume959
Issue number1
DOIs
StatePublished - 3 Jan 2003

Fingerprint

Neurons
Chemical Stimulation
Thorax
Axilla
Pericardium
Bradykinin
Pentobarbital
Dinoprostone
Adenosine
Histamine
Serotonin
Arm
Catheters
Injections

Keywords

  • Descending inhibition
  • Noxious cardiac input
  • Superficial spinal neuron
  • Thoracic spinal cord
  • Visceral nociception

Cite this

Qin, Chao ; Chandler, Margaret J. ; Miller, Kenneth ; Foreman, Robert D. / Chemical activation of cardiac receptors affects activity of superficial and deeper T3-T4 spinal neurons in rats. In: Brain Research. 2003 ; Vol. 959, No. 1. pp. 77-85.
@article{cc1ab6fbb1c0465b9ebe8acf36e10d61,
title = "Chemical activation of cardiac receptors affects activity of superficial and deeper T3-T4 spinal neurons in rats",
abstract = "The purposes of this study were to examine responses of superficial (depth <300 μm) and deeper thoracic spinal neurons to chemical stimulation of cardiac afferents and effects of descending influences on these neurons. Extracellular potentials of single T3-T4 neurons were recorded in pentobarbital anesthetized, paralyzed and ventilated male rats. A catheter was placed in the pericardial sac to administer 0.2 ml of a mixture of algogenic chemicals that contained adenosine (10-3 M), bradykinin, histamine, serotonin, prostaglandin E2 (10-5 M). Fifteen of 55 (27{\%}) superficial neurons responsive to intrapericardial chemicals were compared to 80/169 (47{\%}) deeper neurons. All 15 superficial neurons that responded to cardiac afferents were excited (E), whereas 66 deeper neurons were excited, ten were inhibited and four showed excitation-inhibition. Spontaneous activity of superficial neurons with short-lasting excitatory responses was significantly lower than that of deeper neurons (P<0.05). Somatic receptive fields on chest, axilla, arm and upper back areas were found for 77/95 (81{\%}) neurons that responded to intrapericardial chemicals. The proportion of somatic field properties and their sizes in superficial neurons were similar to deeper neurons. After cervical spinal transection, both spontaneous activity and responses to chemical stimulation of cardiac afferents significantly increased in six out of six neurons excited by intrapericardial injections. Results showed that chemical stimulation of cardiac afferents excited superficial T3-T4 spinal neurons, whereas deeper neurons exhibited multiple patterns of responses. Some characteristics of subgroups of superficial neurons were quantitatively different from deeper neurons. Thoracic spinal neurons processing cardiac nociceptive information were under tonic descending inhibition.",
keywords = "Descending inhibition, Noxious cardiac input, Superficial spinal neuron, Thoracic spinal cord, Visceral nociception",
author = "Chao Qin and Chandler, {Margaret J.} and Kenneth Miller and Foreman, {Robert D.}",
year = "2003",
month = "1",
day = "3",
doi = "10.1016/S0006-8993(02)03728-9",
language = "English",
volume = "959",
pages = "77--85",
journal = "Brain Research",
issn = "0006-8993",
publisher = "Elsevier",
number = "1",

}

Chemical activation of cardiac receptors affects activity of superficial and deeper T3-T4 spinal neurons in rats. / Qin, Chao; Chandler, Margaret J.; Miller, Kenneth; Foreman, Robert D.

In: Brain Research, Vol. 959, No. 1, 03.01.2003, p. 77-85.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Chemical activation of cardiac receptors affects activity of superficial and deeper T3-T4 spinal neurons in rats

AU - Qin, Chao

AU - Chandler, Margaret J.

AU - Miller, Kenneth

AU - Foreman, Robert D.

PY - 2003/1/3

Y1 - 2003/1/3

N2 - The purposes of this study were to examine responses of superficial (depth <300 μm) and deeper thoracic spinal neurons to chemical stimulation of cardiac afferents and effects of descending influences on these neurons. Extracellular potentials of single T3-T4 neurons were recorded in pentobarbital anesthetized, paralyzed and ventilated male rats. A catheter was placed in the pericardial sac to administer 0.2 ml of a mixture of algogenic chemicals that contained adenosine (10-3 M), bradykinin, histamine, serotonin, prostaglandin E2 (10-5 M). Fifteen of 55 (27%) superficial neurons responsive to intrapericardial chemicals were compared to 80/169 (47%) deeper neurons. All 15 superficial neurons that responded to cardiac afferents were excited (E), whereas 66 deeper neurons were excited, ten were inhibited and four showed excitation-inhibition. Spontaneous activity of superficial neurons with short-lasting excitatory responses was significantly lower than that of deeper neurons (P<0.05). Somatic receptive fields on chest, axilla, arm and upper back areas were found for 77/95 (81%) neurons that responded to intrapericardial chemicals. The proportion of somatic field properties and their sizes in superficial neurons were similar to deeper neurons. After cervical spinal transection, both spontaneous activity and responses to chemical stimulation of cardiac afferents significantly increased in six out of six neurons excited by intrapericardial injections. Results showed that chemical stimulation of cardiac afferents excited superficial T3-T4 spinal neurons, whereas deeper neurons exhibited multiple patterns of responses. Some characteristics of subgroups of superficial neurons were quantitatively different from deeper neurons. Thoracic spinal neurons processing cardiac nociceptive information were under tonic descending inhibition.

AB - The purposes of this study were to examine responses of superficial (depth <300 μm) and deeper thoracic spinal neurons to chemical stimulation of cardiac afferents and effects of descending influences on these neurons. Extracellular potentials of single T3-T4 neurons were recorded in pentobarbital anesthetized, paralyzed and ventilated male rats. A catheter was placed in the pericardial sac to administer 0.2 ml of a mixture of algogenic chemicals that contained adenosine (10-3 M), bradykinin, histamine, serotonin, prostaglandin E2 (10-5 M). Fifteen of 55 (27%) superficial neurons responsive to intrapericardial chemicals were compared to 80/169 (47%) deeper neurons. All 15 superficial neurons that responded to cardiac afferents were excited (E), whereas 66 deeper neurons were excited, ten were inhibited and four showed excitation-inhibition. Spontaneous activity of superficial neurons with short-lasting excitatory responses was significantly lower than that of deeper neurons (P<0.05). Somatic receptive fields on chest, axilla, arm and upper back areas were found for 77/95 (81%) neurons that responded to intrapericardial chemicals. The proportion of somatic field properties and their sizes in superficial neurons were similar to deeper neurons. After cervical spinal transection, both spontaneous activity and responses to chemical stimulation of cardiac afferents significantly increased in six out of six neurons excited by intrapericardial injections. Results showed that chemical stimulation of cardiac afferents excited superficial T3-T4 spinal neurons, whereas deeper neurons exhibited multiple patterns of responses. Some characteristics of subgroups of superficial neurons were quantitatively different from deeper neurons. Thoracic spinal neurons processing cardiac nociceptive information were under tonic descending inhibition.

KW - Descending inhibition

KW - Noxious cardiac input

KW - Superficial spinal neuron

KW - Thoracic spinal cord

KW - Visceral nociception

UR - http://www.scopus.com/inward/record.url?scp=0037414739&partnerID=8YFLogxK

U2 - 10.1016/S0006-8993(02)03728-9

DO - 10.1016/S0006-8993(02)03728-9

M3 - Article

C2 - 12480160

AN - SCOPUS:0037414739

VL - 959

SP - 77

EP - 85

JO - Brain Research

JF - Brain Research

SN - 0006-8993

IS - 1

ER -