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Long-lasting inhibition of the cardiovascular responses to glutamate and the baroreceptor reflex elicited by neuropeptide Y injected into the nucleus tractus solitarius of the rat

Grundemar, L LU ; Wahlestedt, C and Reis, D J (1991) In Neuroscience Letters 122(1). p.135-139
Abstract

Neuropeptide Y (NPY) microinjected unilaterally into the nucleus tractus solitarii (NTS) of anesthetized paralyzed rats elicits a gradual dose-dependent and reversible fall in arterial pressure (AP) and heart rate (HR) lasting 20 min. It also abolished the brief (less than 1 min) dose-dependent and reversible fall of AP and HR elicited by L-glutamate (L-Glu) injected into the nucleus. The blockade of L-Glu by NPY appeared gradually and was prolonged, lasting over 2 h, and recovering by 24 h. It was not replicated by desamido-NPY or galanin. Unlike 2% lidocaine it did not block the hypotension elicited by focal electrical stimulation at the injection site indicating the response was not that of a local anesthetic. Bilateral injection of... (More)

Neuropeptide Y (NPY) microinjected unilaterally into the nucleus tractus solitarii (NTS) of anesthetized paralyzed rats elicits a gradual dose-dependent and reversible fall in arterial pressure (AP) and heart rate (HR) lasting 20 min. It also abolished the brief (less than 1 min) dose-dependent and reversible fall of AP and HR elicited by L-glutamate (L-Glu) injected into the nucleus. The blockade of L-Glu by NPY appeared gradually and was prolonged, lasting over 2 h, and recovering by 24 h. It was not replicated by desamido-NPY or galanin. Unlike 2% lidocaine it did not block the hypotension elicited by focal electrical stimulation at the injection site indicating the response was not that of a local anesthetic. Bilateral injection of NPY into the NTS resulted, after an initial fall, in an elevation of AP (+48 +/- 10.6 mmHg). At this time the reflex bradycardia evoked by elevating AP with phenylephrine was markedly reduced. We conclude that in the NTS, NPY antagonizes the actions of L-Glu and may attenuate baroreceptor reflexes. Since the NTS is richly innervated by NPY neurons and contains many NPY binding sites and since primary baroreceptor afferents appear to be glutamatergic the results suggested that NPY may serve in NTS as a long-term regulator of baroreceptor reflex activity.

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publication status
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subject
keywords
Animals, Blood Pressure/drug effects, Dose-Response Relationship, Drug, Electric Stimulation, Excitatory Amino Acid Antagonists, Glutamates/pharmacology, Glutamic Acid, Heart Rate/drug effects, Hemodynamics/drug effects, Injections, Male, Medulla Oblongata, Microinjections, Neuropeptide Y/administration & dosage, Pressoreceptors/drug effects, Rats, Rats, Inbred Strains, Reflex/drug effects, Stereotaxic Techniques
in
Neuroscience Letters
volume
122
issue
1
pages
135 - 139
publisher
Elsevier
external identifiers
  • pmid:1676143
  • scopus:0026068979
ISSN
0304-3940
DOI
10.1016/0304-3940(91)90211-b
language
English
LU publication?
yes
id
7083675a-f2f3-457c-80b1-a103cdab1640
date added to LUP
2019-09-03 14:11:55
date last changed
2025-01-09 21:52:38
@article{7083675a-f2f3-457c-80b1-a103cdab1640,
  abstract     = {{<p>Neuropeptide Y (NPY) microinjected unilaterally into the nucleus tractus solitarii (NTS) of anesthetized paralyzed rats elicits a gradual dose-dependent and reversible fall in arterial pressure (AP) and heart rate (HR) lasting 20 min. It also abolished the brief (less than 1 min) dose-dependent and reversible fall of AP and HR elicited by L-glutamate (L-Glu) injected into the nucleus. The blockade of L-Glu by NPY appeared gradually and was prolonged, lasting over 2 h, and recovering by 24 h. It was not replicated by desamido-NPY or galanin. Unlike 2% lidocaine it did not block the hypotension elicited by focal electrical stimulation at the injection site indicating the response was not that of a local anesthetic. Bilateral injection of NPY into the NTS resulted, after an initial fall, in an elevation of AP (+48 +/- 10.6 mmHg). At this time the reflex bradycardia evoked by elevating AP with phenylephrine was markedly reduced. We conclude that in the NTS, NPY antagonizes the actions of L-Glu and may attenuate baroreceptor reflexes. Since the NTS is richly innervated by NPY neurons and contains many NPY binding sites and since primary baroreceptor afferents appear to be glutamatergic the results suggested that NPY may serve in NTS as a long-term regulator of baroreceptor reflex activity.</p>}},
  author       = {{Grundemar, L and Wahlestedt, C and Reis, D J}},
  issn         = {{0304-3940}},
  keywords     = {{Animals; Blood Pressure/drug effects; Dose-Response Relationship, Drug; Electric Stimulation; Excitatory Amino Acid Antagonists; Glutamates/pharmacology; Glutamic Acid; Heart Rate/drug effects; Hemodynamics/drug effects; Injections; Male; Medulla Oblongata; Microinjections; Neuropeptide Y/administration & dosage; Pressoreceptors/drug effects; Rats; Rats, Inbred Strains; Reflex/drug effects; Stereotaxic Techniques}},
  language     = {{eng}},
  month        = {{01}},
  number       = {{1}},
  pages        = {{135--139}},
  publisher    = {{Elsevier}},
  series       = {{Neuroscience Letters}},
  title        = {{Long-lasting inhibition of the cardiovascular responses to glutamate and the baroreceptor reflex elicited by neuropeptide Y injected into the nucleus tractus solitarius of the rat}},
  url          = {{http://dx.doi.org/10.1016/0304-3940(91)90211-b}},
  doi          = {{10.1016/0304-3940(91)90211-b}},
  volume       = {{122}},
  year         = {{1991}},
}