Investigation of thiosemicarbazide free or within chitosan nanoparticles in a murine model of vulvovaginal candidiasis.

Vulvovaginal candidiasis is a serious health problem affecting numerous women around the world. Its treatment is based on antifungals which may not provide an effective cure because of the resistance presented by its etiological pathogens Candida spp. Candida albicans is the most prevalent species related to vulvovaginal candidiasis. Here, we evaluated the in vivo antifungal potential of thiosemicarbazide and thiosemicarbazide encapsulated within chitosan nanoparticles in a murine model of vulvovaginal candidiasis. The results demonstrated the antifungal capacity of free or nanoencapsulated thiosemicarbazide within chitosan to reduce the fungal load in the vaginal tissue of infected mice. In addition, histological analyses indicated the absence or a mild to moderate infection in thiosemicarbazide-treated groups. Statistical tests confirmed the existence of significant differences between the treated and the control groups. Therefore, our results suggest a potential application of thiosemicarbazide and encapsulated thiosemicarbazide as an alternative vulvovaginal candidiasis therapy.

Enhancement of acoustic evoked potentials and impairment of startle reflex induced by reduction of GABAergic control of the neural substrates of aversion in the inferior colliculus.

The neural network of the inferior colliculus (IC), implicated in the generation of defensive behavior to aversive acoustic stimuli, is under tonic GABAergic control. Dopamine also seems to have a modulatory role in these neural circuits. It is still unclear how such changes in transmission of acoustic information influence the motor expression of the defensive behavior. Startle reaction to a sudden noise has been used as an effective way to measure the motor reactivity of rats to fearful acoustic stimuli. In this work we examined the processing of sensorial information--assessed by the recording of auditory evoked potentials (AEP)--and the behavioral effects--evaluated by the freezing and startle responses--during the reduction of GABA levels caused by microinjections of semicarbazide (SMC, 6 microg/0.2 microl), a glutamic acid decarboxylase inhibitor, into the IC. These data were compared to the effects of the overall arousal elicited by apomorphine (APO, 0.5 mg/kg, i.p.). The results obtained show that IC microinjections of SMC induced freezing behavior, enhanced the AEP and impaired the startle reaction to a loud sound. On the other hand, APO changed neither the AEP nor the startle in the same experimental conditions. These results suggest that the release of GABAergic control of the neural substrates of aversion in the IC results in an increased processing of auditory information along with an inhibitory influence on the motor pathways responsible for the startle response.

Flight behavior induced by microinjection of GABA antagonists into periventricular structures in detelencephalated rats.

Behavioral effects of unilateral microinjections into periventricular structures of bicuculline, a classic GABA-A antagonist, and semicarbazide, a glutamic acid decarboxylase blocker, were studied in detelencephalated rats. These drugs produced a behavioral activation together with jumps. However, the characteristics of this behavioral activation differed as the injections were made in dorsal periaqueductal gray matter or medial hypothalamus. These data show close similarities to those observed with intact animals suggesting that GABA-A receptors are involved in the neural control of expression of flight behavior and functions in an intact manner and possibly independent of influences from forebrain structures. At variance with intact animals, these drugs produced contralateral turning behavior when locally injected into MH, pointing to some kind of inhibitory control exerted by telencephalic structures on the expression of circling behavior from diencephalic regions.