ArticleJournal of comparative physiology. B, Biochemical, systemic, and environmental physiology2011
Chronic hypoxic incubation blunts a cardiovascular reflex loop in embryonic American alligator (Alligator mississippiensis).
Article in Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology, 2011. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 12 papers.
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Who cites it
12 citing papers in PubMed, 37 citations in OpenAlex.
- The impact of adult and lifelong hypoxia on ventricle phenotype in zebrafish (American journal of physiology. Regulatory, integrative and comparative physiology · 2025Article
- Developmental plasticity of the cardiovascular system in oviparous vertebrates: effects of chronic hypoxia and interactive stressors in the context of climate change.The Journal of experimental biology · 2024Review
- Hypoxic incubation at 50% of atmospheric levels shifts the cardiovascular response to acute hypoxia in American alligators, Alligator mississippiensis.Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2023Article
- Changes in hemoglobin function and isoform expression during embryonic development in the American alligator,American journal of physiology. Regulatory, integrative and comparative physiology · 2021Article
- Hypoxia-induced reprogramming of the cardiac phenotype in American alligators (Alligator mississippiensis) revealed by quantitative proteomics.Scientific reports · 2019Article
- Chronic captopril treatment reveals the role of ANG II in cardiovascular function of embryonic American alligators (Alligator mississippiensis).Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2018Article
- Cardiovascular adjustments with egg temperature at 90% incubation in embryonic American alligators, Alligator mississippiensis.Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2018Article
- Periods of cardiovascular susceptibility to hypoxia in embryonic american alligators (Alligator mississippiensis).American journal of physiology. Regulatory, integrative and comparative physiology · 2016Article
- Challenges and opportunities in developmental integrative physiology.Comparative biochemistry and physiology. Part A, Molecular & integrative physiology · 2015Review
- Adjustments in cholinergic, adrenergic and purinergic control of cardiovascular function in snapping turtle embryos (Chelydra serpentina) incubated in chronic hypoxia.Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2014Article
- Chronic hypoxic incubation blunts thermally dependent cholinergic tone on the cardiovascular system in embryonic American alligator (Alligator mississippiensis).Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2013Article
- A role for histamine in cardiovascular regulation in late stage embryos of the red-footed tortoise, Chelonoidis carbonaria Spix, 1824.Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology · 2013Article
Corrections and comments
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Authors and funding
3 authors at 2 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Hypoxia is a naturally occurring environmental challenge for embryonic non-avian reptiles, and this study is the first to investigate the impact of chronic hypoxia on a possible chemoreflex loop in a developing non-avian reptile. We measured heart rate and blood pressure in normoxic and hypoxic-incubated (10% O(2)) American alligator embryos (Alligator mississippiensis) at 70 and 90/95% of development. We hypothesized that hypoxic incubation would blunt embryonic alligators' response to a reflex loop stimulated by phenylbiguanide (PBG), a 5-HT(3) receptor agonist that stimulates vagal pulmonary C-fiber afferents. PBG injection caused a hypotensive bradycardia in 70 and 95% of development embryos (paired t tests, P < 0.05), a response similar to mammals breathing inspired air (all injections made through occlusive catheter in tertiary chorioallantoic membrane artery). Hypoxic incubation blunted the bradycardic response to PBG in embryos at 95% of development (two-way ANOVA, P < 0.01). We also demonstrated that the vagally mediated afferent limb of this reflex can be partially or completely blocked in ovo with a 5-HT(3) receptor blockade using ondansetron hydrochloride dihydrate (OHD), with a ganglionic blockade using hexamethonium, or with a cholinergic blockade using atropine. Atropine eliminated the hypotensive and bradycardic responses to PBG, and OHD and hexamethonium significantly blunted these responses. This cardiovascular reflex mediated by the vagus was affected by hypoxic incubation, suggesting that reptilian sympathetic and parasympathetic reflex loops have the potential for developmental plasticity in response to hypoxia. We suggest that the American alligator, with an extended length of time between each developmental stage relative to avian species, may provide an excellent model to test the cardiorespiratory effects of prolonged exposure to changes in atmospheric gases. This extended period allows for lengthy studies at each stage without the transition to a new stage, and the natural occurrence of hypoxia and hypercapnia in crocodilian nests makes this stress ecologically and evolutionarily relevant.
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