Cardiac response to stimulation and stress in the American alligator (Alligator mississippiensis)

Young, Bruce A.; Potter, James M.; Blanchard, Joshua; Knoche, Lucas; Kondrashova, Tatyana

doi:10.1163/15685381-bja10013

Cited by 6 publications

(4 citation statements)

References 16 publications

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“…The CSF exhibited a clear and consistent pattern of pulsations linked to the cardiac cycle (Fig. 1 A, C, D); these pulsations, the effect of tilting on the CSF pressure, and the alligator’s heart rate all agree with previous studies 21 , 22 . While locomoting on the treadmill the alligators exhibited typical limb movements and undulations of the trunk, these resulted in the head sweeping through horizontal arcs (Fig.…”

Section: Discussionsupporting

confidence: 89%

Treadmill locomotion in the American alligator (Alligator mississippiensis) produces dynamic changes in intracranial cerebrospinal fluid pressure

Young

Cramberg

2022

Sci Rep

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To examine the influence of movement on cerebrospinal fluid (CSF) dynamics, intracranial subdural pressure recordings were taken from sub-adult alligators (Alligator mississippiensis) locomoting on a treadmill. Pressure recordings documenting the cardiac, ventilatory, and barostatic influences on the CSF were in good agreement with previous studies. During locomotion the CSF exhibits sinusoidal patterns of pressure change that spanned a mean amplitude of 56 mm Hg, some 16 × the amplitude of the cardiac-linked pulsations. These sinusoidal CSF pulsations were closely linked to the locomotor kinematics, particularly the lateral oscillations of the alligator’s head. Data recorded from the freely moving alligators suggest that fluid inertia, body cavity pressures, and likely other factors all influence the CSF pressure. The clear relationship between movement and CSF pressure described in this study suggests that the paucity of studies examining human CSF dynamics during movement should be addressed.

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Section: Discussionsupporting

confidence: 89%

Treadmill locomotion in the American alligator (Alligator mississippiensis) produces dynamic changes in intracranial cerebrospinal fluid pressure

Young

Cramberg

2022

Sci Rep

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“…In an attempt to determine if bradypnea was associated with the decreased oxygen consumption after infection, we measured respiratory rates in infected and uninfected animals ( Figure 3 B). Similarly, the respiratory rate at ambient temperature (30 °C) was 2.73 ± 0.51 breaths/min, which was similar to those measured by Coulson and Hernandez [ 64 ] at ambient temperature [ 64 ] (1.5–3.3 breaths/min, 23–25 °C) and Campos [ 65 ] (breaths/min, 32 °C). However, the respiratory rate also did not change after acute infection with bacteria ( Figure 3 B).…”

Section: Discussionsupporting

confidence: 85%

Constitutive Innate Immunity and Systemic Responses to Infection of the American Alligator (Alligator mississippiensis)

Merchant,

Hebert,

Salvador

et al. 2024

Animals

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Uninfected alligators (Alligator mississippiensis) exhibited high constitutive levels of hepatic gene expression related to immune function, whereas the highest-expressed hepatic genes of uninfected mice were related to metabolism. Intraperitoneal challenge of mice with bacterial lipopolysaccharide results in dramatic inflammatory effects including peritoneal ascites, febrile response, dramatic alterations in electrophoretic serum profile, and mortality. In contrast, coelomic injection of alligators with 200× the murine LD50 of intraperitoneal bacterial lipopolysaccharide resulted in no changes in serum protein profiles, behavioral effects, mortality, and no coelomic ascites. However, injection of juvenile alligators with live bacteria resulted in a titer-dependent decrease in metabolic rate, as measured by oxygen consumption. These results are the opposite of those observed for mammalian and avian species. The decreased oxygen consumption was not accompanied by changes in heart or respiration rate, indicating that this phenomenon was not due to bradycardia or bradypnea. Interestingly, challenge of alligators with bacteria resulted in the complete expulsion of digestive tract contents within four hours. We interpret these activities as temporary minimization of other biological systemic activities to redirect and devote energy to immune function. The reallocation of resources within an organism to fight infection without increases in metabolic rate has not been described in other animals.

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“…The heart rate of the seven Alligator mississippiensis was recorded while the animals were under anesthesia. The pooled heart rates: immediately post-surgery (mean = 22 bpm), mid-recovery (mean = 23.5 bpm), and immediately upon full recovery (mean 23.9 bpm); did not significantly change over the course of the experiment and are comparable with earlier studies of anesthesia and heart rate in Alligator [ 50 ]. Like the frequency, the amplitude of the cardiac-related CSF pulsations did not vary significantly through the course of the experiments (mean of 3.7 mm Hg, Figure 8 ).…”

Section: Discussionsupporting

confidence: 84%

The Influence of Movement on the Cerebrospinal Fluid Pressure of the American Alligator (Alligator mississippiensis)

Young

Cramberg

2022

Biology

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This study was undertaken to document how the cerebrospinal fluid (CSF) pressure varied during movements and physiological activities. Using surgically implanted pressure catheters; the CSF pressure was recorded from sub-adult American alligators (Alligator mississippiensis) under anesthesia and post-recovery. Pressures were recorded during physiological activities (the cardiac cycle; passive and active ventilation); manual manipulation of the anesthetized animals (foot sweeps; tail oscillations; and body bends); as well as voluntary movements post-recovery (changes in body tone; defensive strikes; and locomotion). The CSF pulsations associated with the cardiac cycle had the lowest mean amplitude (3.7 mm Hg); during active ventilation and defensive strikes; the alligators routinely generated CSF pressure spikes in excess of 100 mm Hg. The recorded CSF pressures appear to be caused by a variety of mechanisms including vascular pressure; fluid inertia; and possible physical displacement of the spinal cord. The results of the study suggest that any model of CSF dynamics or perfusion should incorporate the episodic high-pressure CSF pulsations associated with movement

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Cardiac response to stimulation and stress in the American alligator (Alligator mississippiensis)

Cited by 6 publications

References 16 publications

Treadmill locomotion in the American alligator (Alligator mississippiensis) produces dynamic changes in intracranial cerebrospinal fluid pressure

Treadmill locomotion in the American alligator (Alligator mississippiensis) produces dynamic changes in intracranial cerebrospinal fluid pressure

Constitutive Innate Immunity and Systemic Responses to Infection of the American Alligator (Alligator mississippiensis)

The Influence of Movement on the Cerebrospinal Fluid Pressure of the American Alligator (Alligator mississippiensis)

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