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Papers of the Week

Papers: 11 May 2019 - 17 May 2019

Animal Studies

2019 Aug 01

Am J Physiol Regul Integr Comp Physiol



Sex differences and the role of ovarian hormones in site-specific nociception of SHR rats.


Maitan Santos B, Nascimento GC, Capel CP, Borges GS, Rosolen T, Sabino J PJ, Leite-Panissi CRA, Branco LGS
Am J Physiol Regul Integr Comp Physiol. 2019 Aug 01; 317(2):R223-R231.
PMID: 31091153.


The accurate diagnosis and treatment of pain is dependent upon the knowledge of variables that might alter this response. Some of these variables are the locality of the noxious stimulus, the sex of the individual, and the presence of chronic diseases. Among these chronic diseases, hypertension is considered a serious and silent disease that has been associated with hypoalgesia. The main goal of this study was to evaluate the potential nociceptive differences in spontaneously hypertensive rats (SHR) regarding the locality of the stimulus, the temporomandibular joint or paw, the sex, and the role of ovarian hormones in a model of mechanical nociception (Von Frey test) or formalin-induced inflammatory nociception. Our results indicate that SHR has lower orofacial mechanical nociception beyond the lower mechanical nociception in the paw compared to WKY rats. In a model of formalin-induced inflammatory nociception, SHR also has a decreased nociception compared to normotensive rats. We also sought to evaluate the influence of sex and ovarian hormones on orofacial mechanical nociception in SHR. We observed that female SHR has higher mechanical nociception than male SHR only in the paw, but it has higher formalin-induced orofacial nociception than male SHR. Moreover, the absence of ovarian hormones caused an increase in mean arterial pressure and a decrease in paw nociception in female SHR.