Cited by 16Heart Rate Variability and Autonomic ControlNeuropeptides and Animal PhysiologyRegulation of Appetite and Obesity

Microinjections of α-melanocyte stimulating hormone into the nucleus ambiguus of the rat elicit vagally mediated bradycardia

Open access
Chitravanshi, Vineet C., Bhatt, Suresh, Sapru, Hreday N.·2009·American Journal of Physiology-Regulatory, Integrative and Comparative Physiology

Abstract

Neurons that immunostain for alpha-melanocyte stimulating hormone (alpha-MSH) have been identified in the nucleus ambiguus (nAmb). The presence of mRNA for melanocortin type 4 receptors (MC4Rs) has also been reported in this nucleus. On the basis of this information, it was hypothesized that activation of MC4Rs in the nAmb may play a role in the regulation of cardiac function. This hypothesis was tested in urethane-anesthetized, artificially ventilated, adult male Wistar rats. Microinjections (30 nl) of alpha-MSH (0.1, 0.2, 0.4, 0.8, and 1.2 mM) into the nAmb of anesthetized rats elicited decreases in heart rate (HR; 1.3 +/- 0.6, 3 +/- 1, 11 +/- 2, 46.3 +/- 3, and 43.3 +/- 7 bpm, respectively) and no changes in mean arterial pressure (MAP). Maximum decreases in HR were elicited by 0.8 mM concentration of alpha-MSH. Bradycardic responses to alpha-MSH were similar in unanesthetized midcollicular decerebrate rats. Microinjections of artificial cerebrospinal fluid (30 nl) into the nAmb did not elicit a HR response. Bilateral vagotomy completely abolished alpha-MSH-induced bradycardia. The decreases in HR elicited by alpha-MSH (0.8 mM) were completely blocked by a selective MC4R antagonist. Direct application of alpha-MSH on the nAmb neurons increased their firing, which was blocked by prior applications of the MC4R antagonist. Microinjections of the MC4R antagonist into the nAmb did not alter reflex bradycardic responses elicited by intravenous infusions of phenylephrine, suggesting that MC4Rs did not play a role in mediating the parasympathetic component of baroreflex-induced bradycardia. These results indicated that alpha-MSH microinjections into the nAmb exert excitatory effects on parasympathetic preganglionic nAmb neurons via MC4Rs, leading to bradycardic responses.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1152/ajpregu.90978.2008

Cites

49 of 49 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • α-MSH and γ1-MSH have protective effects in a rat model of transient myocardial infarction followed by reperfusion and in a rat model of permanent coronary artery occlusion.

    “For instance, α-MSH and γ1-MSH have protective effects in a model of transient myocardial infarction (MI) followed by reperfusion as well as in a model of permanent coronary artery occlusion in rats [66].”

    From Role of the brain melanocortins in blood pressure regulation (2017) · cites this paper as [66]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

1 retracted

Flagged first, then by citations

Cited by

Sorted by citations

Authors
Chitravanshi, V. C., Bhatt, S., & Sapru, H. N.
Affiliations
  • Rutgers New Jersey Medical School (US)
  • Rutgers, The State University of New Jersey (US)
Venue
American Journal of Physiology-Regulatory, Integrative and Comparative Physiology
Published
2009-05
Volume
296
Issue
5
Pages
R1402-R1411
ISSN
  • 0363-6119 (ISSN-L)
  • 1522-1490
OpenAlex
W2132111461
Cited by
16
References
49
Citations by year
2022: 1 · 2020: 1 · 2019: 1 · 2017: 1 · 2016: 1 · 2015: 1 · 2014: 1 · 2013: 4 · 2012: 2
FWCI
1.08
Type
journal article
Language
en
Open access
Locations
  • American Journal of Physiology-Regulatory, Integrative and Comparative Physiology (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
National Heart, Lung, and Blood Institute (HL076248, R01HL024347, HL024347, R01HL076248)
Topics
  • Health Sciences › Medicine › Cardiology and Cardiovascular Medicine › Heart Rate Variability and Autonomic Control
  • Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neuropeptides and Animal Physiology
  • Life Sciences › Neuroscience › Endocrine and Autonomic Systems › Regulation of Appetite and Obesity
Keywords
alpha-melanocyte-stimulating hormone, nucleus ambiguus, vagal bradycardia, vagotomy, preganglionic neurons, heart rate regulation, parasympathetic preganglionic neurons, melanocortin system, baroreflex bradycardia, phenylephrine
MeSH terms
alpha-MSH, Animals, Bradycardia, Dose-Response Relationship, Drug, Heart Rate, Male, Medulla Oblongata, Microinjections, Neurons, RNA, Messenger, Vagotomy, Vagus Nerve, Rats, Wistar, Baroreflex, Models, Animal, Receptor, Melanocortin, Type 4, Rats

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review