Rostral ventrolateral medullary but not medullary lateral tegmental field neurons mediate sympatho-sympathetic reflexes in cats

This study was designed to build on past work from this laboratory by testing the hypothesis that medullary lateral tegmental field (LTF) neurons play a critical role in mediating sympathoexcitatory responses to activation of sympathetic afferent fibers. We studied the effects of microinjection of N-methyl-d-aspartate (NMDA) or non-NMDA receptor antagonists or muscimol bilaterally into the LTF on the area under the curve of the computer-averaged sympathoexcitatory potential in the right inferior cardiac nerve elicited by short trains of stimuli applied to afferent fibers in the left inferior cardiac or left splanchnic nerve (CN, SN) of baroreceptor-denervated and vagotomized cats anesthetized with a mixture of diallylbarbiturate and urethane. In contrast to our hypothesis, sympathoexcitatory responses to stimulation of CN (n = 5-7) or SN (n = 4-7) afferent fibers were not significantly affected by these procedures. We then determined whether the rostral and caudal ventrolateral medulla (RVLM, CVLM) and nucleus tractus solitarius (NTS) were involved in mediating these reflexes. Blockade of non-NMDA, but not NMDA, receptors in the RVLM significantly reduced the area under the curve of the sympathoexcitatory responses to electrical stimulation of either CN (P = 0.0110; n = 6) or SN (P = 0.0131; n = 5) afferent fibers. Neither blockade of excitatory amino acid receptors nor chemical inactivation of CVLM or NTS significantly affected the responses. These data show that activation of non-NMDA receptors in the RVLM is a critical step in mediating the sympatho-sympathetic reflex.

Medienart:

E-Artikel

Erscheinungsjahr:

2010

Erschienen:

2010

Enthalten in:

Zur Gesamtaufnahme - volume:299

Enthalten in:

American journal of physiology. Regulatory, integrative and comparative physiology - 299(2010), 5 vom: 22. Nov., Seite R1269-78

Sprache:

Englisch

Beteiligte Personen:

Barman, Susan M [VerfasserIn]
Orer, Hakan S [VerfasserIn]

Links:

Volltext

Themen:

Excitatory Amino Acid Antagonists
GABA-A Receptor Agonists
Journal Article
Receptors, N-Methyl-D-Aspartate
Research Support, N.I.H., Extramural

Anmerkungen:

Date Completed 01.12.2010

Date Revised 17.03.2022

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1152/ajpregu.00422.2010

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM201288230