Altered cardiovascular responses to glutamate and acetylcholine microinjected into the nucleus tractus solitarii of the SHR

2020 ◽  
pp. 99-107
Author(s):  
William T. Talman ◽  
Stephen J. Lewis
Keyword(s):  
Cardiovascular Responses ◽  
Nucleus Tractus Solitarii

Glycine microinjected into nucleus tractus solitarii of rat acts through cholinergic mechanisms

1991 ◽  
Vol 260 (4) ◽  
pp. H1326-H1331 ◽  
Author(s):  
W. T. Talman ◽  
J. M. Colling ◽  
S. C. Robertson
Keyword(s):  
Heart Rate ◽  
Nmda Receptor ◽  
Arterial Pressure ◽  
Cardiovascular Responses ◽  
Cardiovascular Regulation ◽  
Nucleus Tractus Solitarii ◽  
Receptor Blockade ◽  
Receptor Complex ◽  
Cholinergic Mechanisms ◽  
Nmda Receptor Complex

Previous studies have demonstrated the release of glycine from neurotransmitter pools in the region of the nucleus tractus solitarii (NTS) where cardiovascular afferents terminate. Microinjection of glycine into NTS elicits decreases in arterial pressure and heart rate; these effects are also produced by glutamate or acetylcholine. As glycine may act both at the N-methyl-D-aspartate (NMDA)-receptor complex and centrally to release acetylcholine, we have sought to determine whether the cardiovascular responses to exogenous glycine are mediated through glutamatergic or cholinergic mechanisms. Responses to glycine microinjected into the NTS of anesthetized rats were not affected by blockade of the NMDA receptor complex but, like acetylcholine, were blocked by muscarinic receptor blockade. Physostigmine prolonged responses to glycine. Subthreshold doses of glycine, which augmented responses to acetylcholine microinjected into NTS, either decreased or had no effect on glutamate or NMDA. This study supports a role for glycine in cardiovascular regulation by the NTS and suggests that the actions of glycine may be effected, at least in part, through cholinergic mechanisms.

scholarly journals Cardiovascular responses to L-DOPA microinjected into the nucleus tractus solitarii of the rat

1992 ◽  
Vol 58 ◽  
pp. 49
Author(s):  
Takao Kubo ◽  
Jin-Liang Yue ◽  
Yoshio Goshima ◽  
Shinichi Nakamura ◽  
Yoshimi Misu
Keyword(s):  
Cardiovascular Responses ◽  
Nucleus Tractus Solitarii

Histamine receptor H1 in the nucleus tractus solitarii regulates arterial pressure and heart rate in rats

2011 ◽  
Vol 301 (2) ◽  
pp. H523-H529 ◽  
Author(s):  
Mohammad E. Bhuiyan ◽  
Hidefumi Waki ◽  
Sabine S. Gouraud ◽  
Miwa Takagishi ◽  
Akira Kohsaka ◽  
...  
Keyword(s):  
Heart Rate ◽  
Arterial Pressure ◽  
Cardiovascular Responses ◽  
Histamine Receptor ◽  
Cardiovascular Regulation ◽  
Nucleus Tractus Solitarii ◽  
Central Brain ◽  
Specific Antagonist ◽  
Dose Dependent ◽  
The Brain

Axons of histamine (HA)-containing neurons are known to project from the posterior hypothalamus to many areas of the brain, including the nucleus tractus solitarii (NTS), a central brain structure that plays an important role in regulating arterial pressure. However, the functional significance of NTS HA is still not fully established. In this study, we microinjected HA or 2-pyridylethylamine, a HA-receptor H1-specific agonist, into the NTS of urethane-anesthetized Wister rats to identify the potential functions of NTS HA on cardiovascular regulation. When HA or H1-receptor-specific agonist was bilaterally microinjected into the NTS, mean arterial pressure (MAP) and heart rate (HR) were significantly increased, whereas pretreatment with the H1-receptor-specific antagonist cetirizine into the NTS significantly inhibited the cardiovascular responses. The maximal responses of MAP and HR changes induced by HA or H1-receptor-specific agonist were dose dependent. We also confirmed gene expression of HA receptors in the NTS and that the expression level of H1 mRNA was higher than that of the other subtypes. In addition, we found that H1 receptors are mainly expressed in neurons of the NTS. These findings suggested that HA within the NTS may play a role in regulating cardiovascular homeostasis via activation of H1 receptors expressed in the NTS neurons.

NMDA receptors in nucleus tractus solitarii are linked to soluble guanylate cyclase

2004 ◽  
Vol 286 (4) ◽  
pp. H1521-H1527 ◽  
Author(s):  
Deoclecio A. Chianca ◽  
Li-Hsien Lin ◽  
Deidre Nitschke Dragon ◽  
William T. Talman
Keyword(s):  
Arterial Pressure ◽  
Guanylate Cyclase ◽  
Metabotropic Glutamate Receptors ◽  
Soluble Guanylate Cyclase ◽  
Cardiovascular Responses ◽  
Nucleus Tractus Solitarii ◽  
Sprague Dawley ◽  
Metabotropic Receptors ◽  
Ionotropic Receptor ◽  
Metabotropic Receptor

We sought to test the hypothesis that cardiovascular responses to activation of ionotropic, but not metabotropic, glutamate receptors in the nucleus tractus solitarii (NTS) depend on soluble guanylate cyclase (sGC) and that inhibition of sGC would attenuate baroreflex responses to changes in arterial pressure. In adult male Sprague-Dawley rats anesthetized with chloralose, the ionotropic receptor agonists N-methyl-d-aspartate (NMDA) and dl-α-amino-3-hydroxy-5-methylisoxazole-propionic acid (AMPA) and the metabotropic receptor agonist trans-dl-amino-1,3-cyclopentane-dicarboxylic acid (ACPD) were microinjected into the NTS before and after microinjection of sGC inhibitors at the same site. Inhibition of sGC produced significant dose-dependent attenuation of cardiovascular responses to NMDA but did not alter responses produced by injection of AMPA or ACPD. Bilateral inhibition of sGC did not alter arterial pressure, nor did it attenuate baroreflex responses to pharmacologically induced changes in arterial pressure. This study links sGC with NMDA, but not AMPA or metabotropic, receptors in cardiovascular signal transduction through NTS.

Neurotransmission of autonomic components of aortic baroreceptor afferents in the NTS of awake rats

2000 ◽  
Vol 279 (1) ◽  
pp. H67-H75 ◽  
Author(s):  
Benedito H. Machado ◽  
Jaci A. Castania ◽  
Leni G. H. Bonagamba ◽  
Hélio C. Salgado
Keyword(s):  
Electrical Stimulation ◽  
Nmda Receptors ◽  
Aspartic Acid ◽  
Cardiovascular Responses ◽  
Nucleus Tractus Solitarii ◽  
Ionotropic Receptors ◽  
Aortic Depressor Nerve ◽  
Additional Reduction ◽  
Hypotensive Response ◽  
Awake Rats

The effect of sequential blockade of N-methyl-d-aspartic acid (NMDA) receptors with dl-2-amino-5-phosphonopentanoic acid (AP-5) and non-NMDA receptors with 6,7-dinitroquinoxaline-2,3 dione (DNQX) in the nucleus tractus solitarii (NTS) on the cardiovascular responses to electrical stimulation (ES) of the aortic depressor nerve (ADN) was evaluated in awake rats. Two protocols were used. In protocol 1, bilateral microinjection of AP-5 into the NTS ( n = 7) reduced the hypotensive response to ES of the ADN; subsequent microinjection of DNQX produced additional reduction in this response. AP-5 reduced the bradycardic response, and DNQX almost abolished this response. In protocol 2, bilateral microinjection of DNQX into the NTS ( n = 6) reduced the hypotensive response, and subsequent microinjection of AP-5 significantly reduced this response. DNQX produced a significant reduction in bradycardic response, and AP-5 abolished this response. The data indicate that processing of the parasympathetic component of the NTS aortic baroreceptor afferents is mediated by both NMDA and non-NMDA receptors, whereas processing of the sympathoinhibitory component seems to be only partially mediated by ionotropic receptors.

NO formation in nucleus tractus solitarii attenuates pressor response evoked by skeletal muscle afferents

2001 ◽  
Vol 280 (5) ◽  
pp. H2371-H2379 ◽  
Author(s):  
Jianhua Li ◽  
Jeffrey T. Potts
Keyword(s):  
Skeletal Muscle ◽  
Muscle Contraction ◽  
Pressor Response ◽  
Extracellular Fluid ◽  
Cardiovascular Responses ◽  
Muscle Afferents ◽  
Nucleus Tractus Solitarii ◽  
Triceps Surae ◽  
No Formation ◽  
Fos Protein

We have previously shown that static muscle contraction induces the expression of c-Fos protein in neurons of the nucleus tractus solitarii (NTS) and that some of these cells were codistributed with neuronal NADPH-diaphorase [nitric oxide (NO) synthase]-positive fibers. In the present study, we sought to determine the role of NO in the NTS in mediating the cardiovascular responses elicited by skeletal muscle afferent fibers. Static contraction of the triceps surae muscle was induced by electrical stimulation of the L7 and S1 ventral roots in anesthetized cats. Muscle contraction during microdialysis of artificial extracellular fluid increased mean arterial pressure (MAP) and heart rate (HR) 51 ± 9 mmHg and 18 ± 3 beats/min, respectively. Microdialysis ofl-arginine (10 mM) into the NTS to locally increase NO formation attenuated the increases in MAP (30 ± 7 mmHg, P < 0.05) and HR (14 ± 2 beats/min, P > 0.05) during contraction. Microdialysis ofd-arginine (10 mM) did not alter the cardiovascular responses evoked by muscle contraction. Microdialysis of N G-nitro-l-arginine methyl ester (2 mM) during contraction attenuated the effects ofl-arginine on the reflex cardiovascular responses. These findings demonstrate that an increase in NO formation in the NTS attenuates the pressor response to static muscle contraction, indicating that the NO system plays a role in mediating the cardiovascular responses to static muscle contraction in the NTS.

Evidence for a kynurenate-insensitive glutamate receptor in nucleus tractus solitarii

1992 ◽  
Vol 262 (5) ◽  
pp. H1611-H1615 ◽  
Author(s):  
C. Pawloski-Dahm ◽  
F. J. Gordon
Keyword(s):  
Amino Acid ◽  
Dicarboxylic Acid ◽  
Receptor Antagonist ◽  
Glutamate Receptor ◽  
Excitatory Amino Acid ◽  
Cardiovascular Responses ◽  
Nucleus Tractus Solitarii ◽  
Baroreceptor Reflexes ◽  
Pharmacological Blockade ◽  
Baroreceptor Activation

Previous studies have shown that pharmacological blockade of ionotropic excitatory amino acid (EAA) receptors in the nucleus tractus solitarii (NTS) with kynurenate (Kyn) abolishes baroreceptor reflexes but fails to affect cardiovascular responses evoked by microinjections of L-glutamate (Glu) into the NTS. These observations have raised doubts as to whether Glu is a neurotransmitter of baroreceptor information in the NTS because the pharmacological actions of exogenously administered Glu are not identical to those of the neurotransmitter released in the NTS coincident with baroreceptor activation. One possible explanation for these results is that exogenously administered Glu might act at receptors that are not blocked by Kyn and are not accessible to synaptically released Glu in the NTS baroreflex pathway. The purpose of this study was to determine if Kyn-insensitive Glu receptors are present in the NTS. One candidate for this Kyn-insensitive receptor is the metabotropic EAA receptor that is selectively activated by trans-DL-1-amino-1,3-cyclopentane-dicarboxylic acid (ACPD). Microinjections of ACPD into the NTS of anesthetized rats produced dose-related depressor responses that were not reduced by Kyn or by pretreatment with the putative ACPD receptor antagonist L-2-amino-3-phosphonopropionate (L-AP-3). Similarly, depressor responses produced by Glu also were not affected by Kyn or by L-AP-3. These data demonstrate the presence of a Kyn-insensitive Glu receptor in the NTS. Moreover, they suggest that the failure of Kyn to reduce cardiovascular responses evoked by Glu injections into the NTS can be explained by an action of Glu at Kyn-insensitive ACPD receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Sign in / Sign up

Export Citation Format

Share Document