Seasonal variation of hypoxic and hypercarbic ventilatory responses in the lizard Tropidurus torquatus

Longhini, Leonardo S.; Porto, Lays; Rocha, Aline C.G.; Bícego, Kênia C.; Klein, Wilfried; Gargaglioni, Luciane H.

doi:10.1016/j.cbpa.2019.110534

Cited by 6 publications

(2 citation statements)

References 54 publications

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“…In addition, ventilation during hypoxia was continuous during both phases, what agrees with the usual response to hypoxia that is a shortening of the T NVP with or without an increase fR or V T 5 . Additionally, the green iguana seems to be less sensitive to changes in ambient PO 2 than to variations in PCO 2 such as other species of lizards like Tropidurus torquatus , Lacerta sicula , Lacerta viridis and Uromastyx aegyptius microlepis 8 , 52 , 53 .…”

Section: Discussionmentioning

confidence: 99%

Influence of light/dark cycle and orexins on breathing control in green iguanas (Iguana iguana)

Fonseca

Vicente

Fournier

et al. 2020

Sci Rep

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Light/dark cycle affects the physiology of vertebrates and hypothalamic orexin neurons (ORX) are involved in this function. The breathing pattern of the green iguana changes from continuous to episodic across the light/dark phases. Since the stimulatory actions of ORX on breathing are most important during arousal, we hypothesized that ORX regulates changes of breathing pattern in iguanas. Thus, we: (1) Localized ORX neurons with immunohistochemistry; (2) Quantified cyclic changes in plasma orexin-A levels by ELISA; (3) Compared breathing pattern at rest and during hypoxia and hypercarbia; (4) Evaluated the participation of the ORX receptors in ventilation with intracerebroventricular microinjections of ORX antagonists during light and dark phases. We show that the ORX neurons of I. iguana are located in the periventricular hypothalamic nucleus. Orexin-A peaks during the light/active phase and breathing parallels these cyclic changes: ventilation is higher during the light phase than during the dark phase. However, inactivation of ORX-receptors does not affect the breathing pattern. Iguanas increase ventilation during hypoxia only during the light phase. Conversely, CO2 promotes post-hypercarbic hyperpnea during both phases. We conclude that ORXs potentiate the post-hypercarbic (but not the hypoxic)-drive to breathe and are not involved in light/dark changes in the breathing pattern.

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Section: Discussionmentioning

confidence: 99%

Influence of light/dark cycle and orexins on breathing control in green iguanas (Iguana iguana)

Fonseca

Vicente

Fournier

et al. 2020

Sci Rep

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“…The genus Tropidurus comprises habitat specialists but also generalist species (see Werneck et al, 2015), and records suggest that some species are relatively prone to occupy new niches and persist despite the surrounding urban growth (Rand and Rand, 1966). Another positive aspect of Tropidurus lizards for studies focusing on phenotypic aspects of species found in urban sites is the extensive literature available for eco-morphology (e.g., Kohlsdorf et al, 2001;Kohlsdorf et al, 2008;Grizante et al, 2010;Tulli et al, 2016), behavior (e.g., Leirião et al, 2019;Rodrigues and Kohlsdorf, 2019), locomotion (Kohlsdorf and Navas, 2012;Brandt et al, 2015) and physiology (Longhini et al, 2019) in this group, including information for development (Py-Daniel et al, 2017;Rossigalli-Costa et al, 2021) and thermal relationships (Kohlsdorf and Navas, 2006;Leirião et al, 2019;Piantoni et al, 2019) of species found in urban areas. In this study, we isolated temperature effects from other environmental parameters likely affected by urbanization (e.g., hydrological regimes or pollutants) and evaluate developmental plasticity in offspring of a Tropidurus species commonly found in Brazilian cities.…”

Section: Introductionmentioning

confidence: 99%

Native Lizards Living in Brazilian Cities: Effects of Developmental Environments on Thermal Sensitivity and Morpho-Functional Associations of Locomotion

Rossigalli-Costa

Kohlsdorf

2022

Front. Physiol.

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Environmental conditions often affect developmental processes and consequently influence the range of phenotypic variation expressed at population level. Expansion of urban sites poses new challenges for native species, as urbanization usually affects the intensity of solar exposure and shade availability, determining the thermal regimes organisms are exposed to. In this study, we evaluate the effects of different developmental conditions in a Tropidurus lizard commonly found in Brazilian urban sites. After incubating embryos of Tropidurus catalanensis in two different thermal regimes (Developmental Environments [DE]: cold 24°C and warm 30°C), we measured morphological traits in the neonates and quantified locomotor performance in horizontal and vertical surfaces at three temperatures [Test Temperatures (TT) = 24°C, 30°C and 36°C]. Results indicate effects of developmental temperatures on morphological features, expressing functional implications that might be decisive for the viability of T. catalanensis in urbanized areas. Lizards ran similarly on horizontal and vertical surfaces, and isolated analyses did not identify significant effects of DE or TT on the sprint speeds measured. Absolute Vmax (i.e., the maximum sprint speed reached among all TTs) positively correlated with body size (SVL), and neonates from the warm DE (30°C) were larger than those from the cold DE (24°C). Morpho-functional associations of absolute Vmax also involved pelvic girdle width and forelimb, hindlimb, trunk, and tail lengths. Emerging discussions aim to understand how animals cope with abrupt environmental shifts, a likely common challenge in urbanized sites. Our findings add a new dimension to the topic, providing evidence that temperature, an environmental parameter often affected by urbanization, influences the thermal sensitivity of locomotion and the morphological profile of T. catalanensis neonates. Thermal sensitivity of specific developmental processes may influence the ability of these lizards to remain in habitats that change fast, as those suffering rapid urbanization due to city growth.

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Control of Breathing in Ectothermic Vertebrates

Milsom

Gilmour

Perry

et al. 2022

Comprehensive Physiology

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Seasonal variation of hypoxic and hypercarbic ventilatory responses in the lizard Tropidurus torquatus

Cited by 6 publications

References 54 publications

Influence of light/dark cycle and orexins on breathing control in green iguanas (Iguana iguana)

Influence of light/dark cycle and orexins on breathing control in green iguanas (Iguana iguana)

Native Lizards Living in Brazilian Cities: Effects of Developmental Environments on Thermal Sensitivity and Morpho-Functional Associations of Locomotion

Control of Breathing in Ectothermic Vertebrates

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