Pressor response from rostral dorsomedial medulla is mediated by excitatory amino acid receptors in rostral VLM

Y. Hirooka, J. W. Polson, R. A L Dampney

Research output: Contribution to journalArticle

Abstract

Excitatory amino acid (EAA) receptors in the rostral part of the ventrolateral medulla (VLM) have been shown to mediate pressor responses elicited by stimulation of various peripheral afferent fibers as well as other central nuclei. This study tested the hypothesis that these receptors are a critical component in the central pathway mediating the powerful pressor response that is produced by stimulation of a group of neurons within a circumscribed region in the rostral dorsomedial medulla (RDM). In anesthetized rabbits, the pressor response elicited by unilateral microinjection of glutamate into this RDM region was measured before and after injection of kynurenic acid (Kyn), a broad-spectrum EAA receptor antagonist, into the physiologically identified pressor region of either the ipsilateral or contralateral rostral VLM. The pressor response to RDM stimulation was greatly reduced (to 24 ± 4% of control) 5-10 min after injection of Kyn (but not the vehicle solution) into the ipsilateral rostral VLM; this response returned completely to its control value within 30-60 min after Kyn injection. By contrast, after Kyn injection into the contralateral rostral VLM, the pressor response to RDM stimulation was not affected (106 ± 15% of control). The results indicate that the descending pressor pathway from the RDM to the spinal cord is mediated by EAA receptors in the rostral VLM pressor region. Furthermore, the pathway from the RDM to the rostral VLM is predominantly, if not exclusively, ipsilateral.

Original languageEnglish
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume267
Issue number1 36-1
Publication statusPublished - 1994
Externally publishedYes

Fingerprint

Kynurenic Acid
Glutamate Receptors
Injections
Excitatory Amino Acid Antagonists
Microinjections
Glutamic Acid
Spinal Cord
Rabbits
Neurons

All Science Journal Classification (ASJC) codes

  • Physiology

Cite this

Pressor response from rostral dorsomedial medulla is mediated by excitatory amino acid receptors in rostral VLM. / Hirooka, Y.; Polson, J. W.; Dampney, R. A L.

In: American Journal of Physiology - Regulatory Integrative and Comparative Physiology, Vol. 267, No. 1 36-1, 1994.

Research output: Contribution to journalArticle

@article{fa71b10515654dd7a89fa2578136fac0,
title = "Pressor response from rostral dorsomedial medulla is mediated by excitatory amino acid receptors in rostral VLM",
abstract = "Excitatory amino acid (EAA) receptors in the rostral part of the ventrolateral medulla (VLM) have been shown to mediate pressor responses elicited by stimulation of various peripheral afferent fibers as well as other central nuclei. This study tested the hypothesis that these receptors are a critical component in the central pathway mediating the powerful pressor response that is produced by stimulation of a group of neurons within a circumscribed region in the rostral dorsomedial medulla (RDM). In anesthetized rabbits, the pressor response elicited by unilateral microinjection of glutamate into this RDM region was measured before and after injection of kynurenic acid (Kyn), a broad-spectrum EAA receptor antagonist, into the physiologically identified pressor region of either the ipsilateral or contralateral rostral VLM. The pressor response to RDM stimulation was greatly reduced (to 24 ± 4{\%} of control) 5-10 min after injection of Kyn (but not the vehicle solution) into the ipsilateral rostral VLM; this response returned completely to its control value within 30-60 min after Kyn injection. By contrast, after Kyn injection into the contralateral rostral VLM, the pressor response to RDM stimulation was not affected (106 ± 15{\%} of control). The results indicate that the descending pressor pathway from the RDM to the spinal cord is mediated by EAA receptors in the rostral VLM pressor region. Furthermore, the pathway from the RDM to the rostral VLM is predominantly, if not exclusively, ipsilateral.",
author = "Y. Hirooka and Polson, {J. W.} and Dampney, {R. A L}",
year = "1994",
language = "English",
volume = "267",
journal = "American Journal of Physiology - Heart and Circulatory Physiology",
issn = "0363-6135",
publisher = "American Physiological Society",
number = "1 36-1",

}

TY - JOUR

T1 - Pressor response from rostral dorsomedial medulla is mediated by excitatory amino acid receptors in rostral VLM

AU - Hirooka, Y.

AU - Polson, J. W.

AU - Dampney, R. A L

PY - 1994

Y1 - 1994

N2 - Excitatory amino acid (EAA) receptors in the rostral part of the ventrolateral medulla (VLM) have been shown to mediate pressor responses elicited by stimulation of various peripheral afferent fibers as well as other central nuclei. This study tested the hypothesis that these receptors are a critical component in the central pathway mediating the powerful pressor response that is produced by stimulation of a group of neurons within a circumscribed region in the rostral dorsomedial medulla (RDM). In anesthetized rabbits, the pressor response elicited by unilateral microinjection of glutamate into this RDM region was measured before and after injection of kynurenic acid (Kyn), a broad-spectrum EAA receptor antagonist, into the physiologically identified pressor region of either the ipsilateral or contralateral rostral VLM. The pressor response to RDM stimulation was greatly reduced (to 24 ± 4% of control) 5-10 min after injection of Kyn (but not the vehicle solution) into the ipsilateral rostral VLM; this response returned completely to its control value within 30-60 min after Kyn injection. By contrast, after Kyn injection into the contralateral rostral VLM, the pressor response to RDM stimulation was not affected (106 ± 15% of control). The results indicate that the descending pressor pathway from the RDM to the spinal cord is mediated by EAA receptors in the rostral VLM pressor region. Furthermore, the pathway from the RDM to the rostral VLM is predominantly, if not exclusively, ipsilateral.

AB - Excitatory amino acid (EAA) receptors in the rostral part of the ventrolateral medulla (VLM) have been shown to mediate pressor responses elicited by stimulation of various peripheral afferent fibers as well as other central nuclei. This study tested the hypothesis that these receptors are a critical component in the central pathway mediating the powerful pressor response that is produced by stimulation of a group of neurons within a circumscribed region in the rostral dorsomedial medulla (RDM). In anesthetized rabbits, the pressor response elicited by unilateral microinjection of glutamate into this RDM region was measured before and after injection of kynurenic acid (Kyn), a broad-spectrum EAA receptor antagonist, into the physiologically identified pressor region of either the ipsilateral or contralateral rostral VLM. The pressor response to RDM stimulation was greatly reduced (to 24 ± 4% of control) 5-10 min after injection of Kyn (but not the vehicle solution) into the ipsilateral rostral VLM; this response returned completely to its control value within 30-60 min after Kyn injection. By contrast, after Kyn injection into the contralateral rostral VLM, the pressor response to RDM stimulation was not affected (106 ± 15% of control). The results indicate that the descending pressor pathway from the RDM to the spinal cord is mediated by EAA receptors in the rostral VLM pressor region. Furthermore, the pathway from the RDM to the rostral VLM is predominantly, if not exclusively, ipsilateral.

UR - http://www.scopus.com/inward/record.url?scp=0028095435&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0028095435&partnerID=8YFLogxK

M3 - Article

C2 - 8048637

VL - 267

JO - American Journal of Physiology - Heart and Circulatory Physiology

JF - American Journal of Physiology - Heart and Circulatory Physiology

SN - 0363-6135

IS - 1 36-1

ER -