Stimulation of spinal δ-opioid receptors attenuates the exercise pressor reflex in decerebrate rats

Joyce S. Kim, Marc Kaufman

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

A reflex arising from contracting hindlimb muscle is responsible in part for the increases in arterial pressure and heart rate evoked by exercise. The afferent arm of this reflex comprises group III and IV afferents. δ-Opioid receptors are expressed predominately on the spinal endings of group III afferents, whereas μ-opioid receptors are expressed predominately on the spinal endings of group IV afferents. Using stimuli that activated group III afferents, namely static contraction, calcaneal tendon stretch, and lactic acid injection into the superficial epigastric artery, we tested the hypothesis that, in rats with either patent or ligated femoral arteries, activation of pre-and postsynaptic δ-opioid receptors in the dorsal horn attenuated pressor reflex responses to these stimuli. In rats with patent arteries or ligated femoral arteries, [D-Pen2,5]enkephalin (DPDPE), a δ-opioid agonist injected intrathecally (10 μg in 10 μl), significantly attenuated the pressor responses to contraction, stretch, and lactic acid (all P ± 0.05). Naltrindole, a δ-opioid receptor antagonist, prevented the attenuation. In contrast, DPDPE did not attenuate the pressor response to capsaicin injection into the superficial epigastric artery in either group of rats (both P-0.05). Intrathecal injection of saline (10 μl), the vehicle for DPDPE, had no effect on the pressor responses in either group of rats. We conclude that activation of spinal δ-opioid receptors attenuates reflexes evoked by group III afferents in both freely perfused and ligated rats.

Original languageEnglish (US)
Pages (from-to)R727-R734
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume316
Issue number6
DOIs
StatePublished - Jan 1 2019

Fingerprint

Opioid Receptors
Reflex
D-Penicillamine (2,5)-Enkephalin
Epigastric Arteries
naltrindole
Femoral Artery
Lactic Acid
Spinal Injections
Injections
Achilles Tendon
Narcotic Antagonists
Enkephalins
Capsaicin
Hindlimb
Opioid Analgesics
Arterial Pressure
Arteries
Heart Rate
Muscles

All Science Journal Classification (ASJC) codes

  • Physiology
  • Physiology (medical)

Cite this

@article{f87262fa1b304de69d07c8ab36e981d4,
title = "Stimulation of spinal δ-opioid receptors attenuates the exercise pressor reflex in decerebrate rats",
abstract = "A reflex arising from contracting hindlimb muscle is responsible in part for the increases in arterial pressure and heart rate evoked by exercise. The afferent arm of this reflex comprises group III and IV afferents. δ-Opioid receptors are expressed predominately on the spinal endings of group III afferents, whereas μ-opioid receptors are expressed predominately on the spinal endings of group IV afferents. Using stimuli that activated group III afferents, namely static contraction, calcaneal tendon stretch, and lactic acid injection into the superficial epigastric artery, we tested the hypothesis that, in rats with either patent or ligated femoral arteries, activation of pre-and postsynaptic δ-opioid receptors in the dorsal horn attenuated pressor reflex responses to these stimuli. In rats with patent arteries or ligated femoral arteries, [D-Pen2,5]enkephalin (DPDPE), a δ-opioid agonist injected intrathecally (10 μg in 10 μl), significantly attenuated the pressor responses to contraction, stretch, and lactic acid (all P ± 0.05). Naltrindole, a δ-opioid receptor antagonist, prevented the attenuation. In contrast, DPDPE did not attenuate the pressor response to capsaicin injection into the superficial epigastric artery in either group of rats (both P-0.05). Intrathecal injection of saline (10 μl), the vehicle for DPDPE, had no effect on the pressor responses in either group of rats. We conclude that activation of spinal δ-opioid receptors attenuates reflexes evoked by group III afferents in both freely perfused and ligated rats.",
author = "Kim, {Joyce S.} and Marc Kaufman",
year = "2019",
month = "1",
day = "1",
doi = "10.1152/ajpregu.00013.2019",
language = "English (US)",
volume = "316",
pages = "R727--R734",
journal = "American Journal of Physiology",
issn = "0363-6119",
publisher = "American Physiological Society",
number = "6",

}

TY - JOUR

T1 - Stimulation of spinal δ-opioid receptors attenuates the exercise pressor reflex in decerebrate rats

AU - Kim, Joyce S.

AU - Kaufman, Marc

PY - 2019/1/1

Y1 - 2019/1/1

N2 - A reflex arising from contracting hindlimb muscle is responsible in part for the increases in arterial pressure and heart rate evoked by exercise. The afferent arm of this reflex comprises group III and IV afferents. δ-Opioid receptors are expressed predominately on the spinal endings of group III afferents, whereas μ-opioid receptors are expressed predominately on the spinal endings of group IV afferents. Using stimuli that activated group III afferents, namely static contraction, calcaneal tendon stretch, and lactic acid injection into the superficial epigastric artery, we tested the hypothesis that, in rats with either patent or ligated femoral arteries, activation of pre-and postsynaptic δ-opioid receptors in the dorsal horn attenuated pressor reflex responses to these stimuli. In rats with patent arteries or ligated femoral arteries, [D-Pen2,5]enkephalin (DPDPE), a δ-opioid agonist injected intrathecally (10 μg in 10 μl), significantly attenuated the pressor responses to contraction, stretch, and lactic acid (all P ± 0.05). Naltrindole, a δ-opioid receptor antagonist, prevented the attenuation. In contrast, DPDPE did not attenuate the pressor response to capsaicin injection into the superficial epigastric artery in either group of rats (both P-0.05). Intrathecal injection of saline (10 μl), the vehicle for DPDPE, had no effect on the pressor responses in either group of rats. We conclude that activation of spinal δ-opioid receptors attenuates reflexes evoked by group III afferents in both freely perfused and ligated rats.

AB - A reflex arising from contracting hindlimb muscle is responsible in part for the increases in arterial pressure and heart rate evoked by exercise. The afferent arm of this reflex comprises group III and IV afferents. δ-Opioid receptors are expressed predominately on the spinal endings of group III afferents, whereas μ-opioid receptors are expressed predominately on the spinal endings of group IV afferents. Using stimuli that activated group III afferents, namely static contraction, calcaneal tendon stretch, and lactic acid injection into the superficial epigastric artery, we tested the hypothesis that, in rats with either patent or ligated femoral arteries, activation of pre-and postsynaptic δ-opioid receptors in the dorsal horn attenuated pressor reflex responses to these stimuli. In rats with patent arteries or ligated femoral arteries, [D-Pen2,5]enkephalin (DPDPE), a δ-opioid agonist injected intrathecally (10 μg in 10 μl), significantly attenuated the pressor responses to contraction, stretch, and lactic acid (all P ± 0.05). Naltrindole, a δ-opioid receptor antagonist, prevented the attenuation. In contrast, DPDPE did not attenuate the pressor response to capsaicin injection into the superficial epigastric artery in either group of rats (both P-0.05). Intrathecal injection of saline (10 μl), the vehicle for DPDPE, had no effect on the pressor responses in either group of rats. We conclude that activation of spinal δ-opioid receptors attenuates reflexes evoked by group III afferents in both freely perfused and ligated rats.

UR - http://www.scopus.com/inward/record.url?scp=85066965788&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85066965788&partnerID=8YFLogxK

U2 - 10.1152/ajpregu.00013.2019

DO - 10.1152/ajpregu.00013.2019

M3 - Article

VL - 316

SP - R727-R734

JO - American Journal of Physiology

JF - American Journal of Physiology

SN - 0363-6119

IS - 6

ER -