Speech intelligibility with and without noise in individuals exposed to electronic music

Audiometry is the main way with which hearing is evaluated, because it is a universal and standardized test. Speech tests are difficult to standardize due to the variables involved, their performance in the presence of competitive noise is of great importance. Aim: To characterize speech intelligibility in silence and in competitive noise from individuals exposed to electronically amplified music. Material and Method: It was performed with 20 university students who presented normal hearing thresholds. The speech recognition rate (SRR) was performed after fourteen hours of sound rest after the exposure to electronically amplified music and once again after sound rest, being studied in three stages: without competitive noise, in the presence of Babble-type competitive noise, in monotic listening, in signal/ noise ratio of + 5 dB and with the signal/ noise ratio of 5 dB. Results: There was greater damage in the SRR after exposure to the music and with competitive noise, and as the signal/ noise ratio decreases, the performance of individuals in the test also decreased. Conclusion: The inclusion of competitive noise in the speech tests in the audiological routine is important, because it represents the real disadvantage experienced by individuals in daily listening.

Role of preoptic opioid receptors in the body temperature reduction during hypoxia

Evidence indicates that endogenous opioids play a role in body temperature (Tb) regulation in mammals but no data exist about the involvement of the specific opioid receptors, mu, kappa and delta, in the reduction of Tb induced by hypoxia. Thus, we investigated the participation of these opioid receptors in the anteroventral preoptic region (AVPO) in hypoxic decrease of Th. To this end, Th of unanesthetized Wistar rats was monitored by temperature data loggers before and after intra-AVPO microinjection of the selective kappa-opioid receptor antagonist nor-binaltorphimine dihydrochloride (nor-BNI; 0.1 and 1.0 mu g/100 nL/animal), the selective mu-opioid receptor antagonist D-Phe-Cys-Tyr-D-Trp-Arg-Thr-Pen-Thr-NH(2) cyclic (CTAP; 0.1 and 1.0 mu g/100 nL/animal), and the selective delta-opioid receptor antagonist Naltrindole (0.06 and 0.6 mu g/100 nL/animal) or saline (vehicle, 100 nu animal), during normoxia and hypoxia (7% inspired O(2)). Under normoxia, no effect of opioid antagonists on Th was observed. Hypoxia induced Th to reduce in vehicle group, a response that was inhibited by the microinjection intra-AVPO of nor-BNI. In contrast, CTAP and Naltrindole did not change Th during hypoxia but caused a longer latency for the return of Th to the normoxic values just after low O(2) exposure. Our results indicate the kappa-opioid receptor in the AVPO is important for the reduction of Th during hypoxia while the mu and delta receptors are involved in the increase of Th during normoxia post-hypoxia. (C) 2009 Elsevier B.V. All rights reserved.

GABAergic antagonist blocks the reduction of tonic immobility behavior induced by activation of 5-HT(2) receptors in the basolateral nucleus of the amygdala in guinea pigs

Tonic immobility (TI) is a temporary state of profound motor inhibition induced by situations that generate intense fear, with the objective of protecting an animal from attacks by predators. A preliminary study by our group demonstrated that microinjection into the basolateral nucleus of the amygdala (BLA) of an agonist to 5-HT(1A) and 5-HT(2) receptors promoted a decrease in TI duration. In the current study, the effects of GABAergic stimulation of the BLA and the possible interaction between GABA(A) and 5-HT(2) receptors on TI modulation were investigated. Observation revealed that GABAergic agonist muscimol (0.26 nmol) reduced the duration of TI episodes, while microinjection of the GABAergic antagonist bicuculline (1 nmol) increased TI duration. Additionally, microinjection of 5-HT(2) agonist receptors (alpha-methyl-5-HT, 0.32 nmol) into the BLA decreased TI duration, an effect reversed by pretreatment with bicuculline (at the dose that had no effect per se, 0.2 nmol). Moreover, the activation of GABA(A) and 5-HT(2) receptors in the BLA did not alter the spontaneous motor activity in the open field test. These experiments demonstrated that the activation of GABA(A) and 5-HT(2) receptors of the BLA possibly produce a reduction in unconditioned fear that decreases the TI duration in guinea pigs, but this is not due to increased spontaneous motor activity, which could affect a TI episode nonspecifically. Furthermore, these results suggest an interaction between GABAergic and serotoninergic mechanisms mediated by GABA(A) and 5-HT(2) receptors. In addition, the GABAergic circuit of the BLA presents a tonic inhibitory influence on TI duration. (C) 2009 Elsevier Inc. All rights reserved.