Limits...
Local Application of Sodium Salicylate Enhances Auditory Responses in the Rat's Dorsal Cortex of the Inferior Colliculus.

Patel CR, Zhang H - Front Neurol (2014)

Bottom Line: Sodium salicylate (SS) is a widely used medication with side effects on hearing.Simultaneous application of the drug and a GABAergic receptor agonist produced an effect different from the sum of effects produced by the two drugs released individually.Our results indicate that SS can affect sound-driven activity in the ICd by modulating local GABAergic inhibition.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, University of Windsor , Windsor, ON , Canada.

ABSTRACT
Sodium salicylate (SS) is a widely used medication with side effects on hearing. In order to understand these side effects, we recorded sound-driven local-field potentials in a neural structure, the dorsal cortex of the inferior colliculus (ICd). Using a microiontophoretic technique, we applied SS at sites of recording and studied how auditory responses were affected by the drug. Furthermore, we studied how the responses were affected by combined local application of SS and an agonists/antagonist of the type-A or type-B γ-aminobutyric acid receptor (GABAA or GABAB receptor). Results revealed that SS applied alone enhanced auditory responses in the ICd, indicating that the drug had local targets in the structure. Simultaneous application of the drug and a GABAergic receptor antagonist synergistically enhanced amplitudes of responses. The synergistic interaction between SS and a GABAA receptor antagonist had a relatively early start in reference to the onset of acoustic stimulation and the duration of this interaction was independent of sound intensity. The interaction between SS and a GABAB receptor antagonist had a relatively late start, and the duration of this interaction was dependent on sound intensity. Simultaneous application of the drug and a GABAergic receptor agonist produced an effect different from the sum of effects produced by the two drugs released individually. These differences between simultaneous and individual drug applications suggest that SS modified GABAergic inhibition in the ICd. Our results indicate that SS can affect sound-driven activity in the ICd by modulating local GABAergic inhibition.

No MeSH data available.


Related in: MedlinePlus

Group results (n = 8) obtained at 10 dB above the MT showing effects of individual applications of SS and CGP35348 (two middle bars) and a simultaneous application of the drugs (right bar) on the peak amplitude (A) and latency (B) of the DN. A horizontal line in (A) represent the mean peak amplitude of the DN obtained before drug application. Double stars indicate statistical significance at the level of p < 0.005. A single star indicates statistical significance at a level of p < 0.05. Error bars represent SE.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4231951&req=5

Figure 8: Group results (n = 8) obtained at 10 dB above the MT showing effects of individual applications of SS and CGP35348 (two middle bars) and a simultaneous application of the drugs (right bar) on the peak amplitude (A) and latency (B) of the DN. A horizontal line in (A) represent the mean peak amplitude of the DN obtained before drug application. Double stars indicate statistical significance at the level of p < 0.005. A single star indicates statistical significance at a level of p < 0.05. Error bars represent SE.

Mentions: Group results from eight cases (Figure 8A) confirmed findings from the example shown in Figure 7. At 10 dB above the MT, individual applications of SS and CGP35348 caused significant increases in the peak amplitude of the DN, while simultaneous application of the drugs caused an increase much larger than the sum of those caused by individual applications of the drugs [two-way repeated-measures ANOVA, F(1,7) = 49.99, p < 0.001 for SS; F(1,7) = 22.17, p < 0.005 for CGP35348; F(1,7) = 6.78, p < 0.05 for the interaction between drugs]. Results obtained at other supra-threshold sound-pressure levels were consistent with those obtained at 10 dB above the MT. Group results indicated that SS and CGP35348 did not affect the peak latency of the DN (Figure 8B).


Local Application of Sodium Salicylate Enhances Auditory Responses in the Rat's Dorsal Cortex of the Inferior Colliculus.

Patel CR, Zhang H - Front Neurol (2014)

Group results (n = 8) obtained at 10 dB above the MT showing effects of individual applications of SS and CGP35348 (two middle bars) and a simultaneous application of the drugs (right bar) on the peak amplitude (A) and latency (B) of the DN. A horizontal line in (A) represent the mean peak amplitude of the DN obtained before drug application. Double stars indicate statistical significance at the level of p < 0.005. A single star indicates statistical significance at a level of p < 0.05. Error bars represent SE.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231951&req=5

Figure 8: Group results (n = 8) obtained at 10 dB above the MT showing effects of individual applications of SS and CGP35348 (two middle bars) and a simultaneous application of the drugs (right bar) on the peak amplitude (A) and latency (B) of the DN. A horizontal line in (A) represent the mean peak amplitude of the DN obtained before drug application. Double stars indicate statistical significance at the level of p < 0.005. A single star indicates statistical significance at a level of p < 0.05. Error bars represent SE.
Mentions: Group results from eight cases (Figure 8A) confirmed findings from the example shown in Figure 7. At 10 dB above the MT, individual applications of SS and CGP35348 caused significant increases in the peak amplitude of the DN, while simultaneous application of the drugs caused an increase much larger than the sum of those caused by individual applications of the drugs [two-way repeated-measures ANOVA, F(1,7) = 49.99, p < 0.001 for SS; F(1,7) = 22.17, p < 0.005 for CGP35348; F(1,7) = 6.78, p < 0.05 for the interaction between drugs]. Results obtained at other supra-threshold sound-pressure levels were consistent with those obtained at 10 dB above the MT. Group results indicated that SS and CGP35348 did not affect the peak latency of the DN (Figure 8B).

Bottom Line: Sodium salicylate (SS) is a widely used medication with side effects on hearing.Simultaneous application of the drug and a GABAergic receptor agonist produced an effect different from the sum of effects produced by the two drugs released individually.Our results indicate that SS can affect sound-driven activity in the ICd by modulating local GABAergic inhibition.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Sciences, University of Windsor , Windsor, ON , Canada.

ABSTRACT
Sodium salicylate (SS) is a widely used medication with side effects on hearing. In order to understand these side effects, we recorded sound-driven local-field potentials in a neural structure, the dorsal cortex of the inferior colliculus (ICd). Using a microiontophoretic technique, we applied SS at sites of recording and studied how auditory responses were affected by the drug. Furthermore, we studied how the responses were affected by combined local application of SS and an agonists/antagonist of the type-A or type-B γ-aminobutyric acid receptor (GABAA or GABAB receptor). Results revealed that SS applied alone enhanced auditory responses in the ICd, indicating that the drug had local targets in the structure. Simultaneous application of the drug and a GABAergic receptor antagonist synergistically enhanced amplitudes of responses. The synergistic interaction between SS and a GABAA receptor antagonist had a relatively early start in reference to the onset of acoustic stimulation and the duration of this interaction was independent of sound intensity. The interaction between SS and a GABAB receptor antagonist had a relatively late start, and the duration of this interaction was dependent on sound intensity. Simultaneous application of the drug and a GABAergic receptor agonist produced an effect different from the sum of effects produced by the two drugs released individually. These differences between simultaneous and individual drug applications suggest that SS modified GABAergic inhibition in the ICd. Our results indicate that SS can affect sound-driven activity in the ICd by modulating local GABAergic inhibition.

No MeSH data available.


Related in: MedlinePlus