(891.1) Site-specific regulation of emotional stress responses along the rostrocaudal axis of the insular cortex in rats

Poster Board Number: E375

Carlos Crestani (School of Pharmaceutical Sciences, São Paulo State University (UNESP)), Rodrigo Tomeo (School of Pharmaceutical Sciences, São Paulo State University (UNESP)), Lucas Gomes-de-Souza (School of Pharmaceutical Sciences, São Paulo State University (UNESP)), Ricardo Benini (School of Pharmaceutical Sciences, São Paulo State University (UNESP)), Lilian Reis-Silva (School of Pharmaceutical Sciences, São Paulo State University (UNESP))

The insular cortex (IC) has been described as part of the central network implicated in the behavioral and physiological responses to emotional stress. Besides, it has been reported a site-specific control of physiological functions along the rostrocaudal axis of the IC. Nevertheless, evaluation of a functional topography of the IC in the regulation of the responses to stressful stimuli has never been documented. Therefore, this study aimed to investigate the impact of acute restraint stress in neuronal activation at different sites along the rostrocaudal axis of the IC in rats. Furthermore, we evaluated the involvement of IC rostrocaudal subregions in the cardiovascular responses to acute restraint stress. For this, male Wistar rats (60-days-old) were used. The restraint stress was performed by placing the animals in a cylindrical plastic tube for 60 minutes. For the cardiovascular study, different set of animals had cannula-guide bilaterally implanted into the anterior, rostral posterior of caudal posterior subregions of the IC; and the non-selective synaptic inhibitor CoCl2(1mM/100nL) was microinjected 10 min before the restraint onset. We observed that acute restraint stress increased the number of Fos-immunoreactive cells in the rostral posterior region of the IC (t=2.95, df=14, P=0.0106), while fewer activated cells were identified in the anterior (t=2.44, df=14, P= 0.0276) and caudal posterior (t=2.27, df=14, P=0.0388) regions. Treatment of the anterior region of the IC with CoCl2 did not affect the blood pressure (F(1,15)=0.90, Pgt;0.05) and heart rate (F(1,15)=0.3, Pgt;0.05) increases and the sympathetically-mediated cutaneous vasoconstriction (F(1,15)=2.23, Pgt;0.05) evoked by restraint stress. However, synaptic ablation of the rostral posterior IC decreased the restraint-evoked arterial pressure increase (F(1,21)=5.3, P=0.0313), but without affecting the tachycardia (F(1,21)=4.1, P=0.0561) and the reduction in tail skin temperature (F(1,21)=0.05, Pgt;0.05). Besides, bilateral microinjection of CoCl2 into the caudal posterior IC decreased the tachycardia to restraint stress (F(1,17)=11.3, P=0.0036), but without affecting the blood pressure (F(1,17)= 0.2, Pgt;0.05) and tail skin temperature (F(1,17)= 1.4, Pgt;0.05) responses. Taken together, these findings indicate a site-specific regulation of stress response along the rostrocaudal axis of the IC.

FAPESP (2017/19249-0 and 2019/24478-3), CNPq (304108/2018-9and 431339/2018-0) and PADC-FCF/UNESP.