CONICET | Buscador de Institutos y Recursos Humanos

Behavioral and physiological adaptive responses of animals facing chronic exposure to a singlestressor may allow them to overcome its negative effects for future exposures to similar stressfulsituations. At chemical level, the GABAA/benzodiazepine complex is considered one of the mainreceptor systems involved in the modulation of stress-induced responses. Here, we describe thebehavioral responses of two different lizard species, Liolaemus koslowskyi and Cnemidophorustergolaevigatus exposed to three potential chronic stressful treatments: (a) high temperature, (b)forced swimming, and (c) simulated predator. Additionally, we aimed to determine in those lizardswhether the central-type benzodiazepine receptor (CBR; an allosteric modulator site of the GABAAreceptor) is related to adaptive responses to those stressful stimulations. Our results revealed thatthe simulated predator was the stress condition that showed the largest difference in behavioralresponses between the two species, resembling previously described strategies in nature. Thebasal affinity of CBRs (obtained from undisturbed animals) showed differences between both species, and the simulated predator was the only stressor that altered the affinity of CBRs. L.koslowskyi CBRs showed a decreased receptor affinity, whereas C. tergolaevigatus showed anincreased receptor affinity in comparison to their respective control groups. We show for the firsttime the effects of different types of stressors upon behavioral responses and CBR biochemicalparameters in two lizard species. Our findings suggest a potential GABA/benzodiazepine role inthe ability of lizards to cope with a repeated exposure to a stressful (e.g., predator) condition.

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