Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9436727 | Hearing Research | 2005 | 11 Pages |
Abstract
Physiological control of auditory neural responses is critical for accurate representation of acoustic information, such as sound source localization and speech perception. Central auditory neural responses are almost certainly regulated by a range of mechanisms, including second messenger systems, such as the cAMP pathway. An increase in spontaneous neural discharge is known to accompany cochlear insults. Here we report that an increase in spontaneous as well as tone-evoked discharge can also be induced by pressure application of forskolin, a pharmacological agent that elevates intracellular cAMP level by activating adenyl cyclase. The forskolin induced increase in superior olivary complex (SOC) brainstem neurons is specific, dose-dependent, and reversible, whereas application of artificial cerebrospinal fluid (aCSF, the vehicle) does not alter activity. Forskolin-application also has a relatively greater effect on spontaneous activity compared to tone evoked responses. Blockade of the hyperpolarization-activated current, Ih, by ZD7288, consistently reversed the effects of forskolin. Based on these findings, we propose that the second messenger, cAMP, can significantly modulate neural excitability and spontaneous discharge in SOC neurons, principally by shifting the activation of Ih channels.
Keywords
HCNWGA-HRPcAMP, cyclic-AMPERKSAPKpKaPDE4aCSFcyclic-adenosine monophosphatePSTHLSOdB SPLstandard deviationCNSlateral superior oliveSOCcentral nervous systemspontaneous activityartificial cerebrospinal fluidsuperior olivary complexdecibel sound pressure levelpost-stimulus time histogramStress-activated protein kinaseextracellular signal-regulated kinase
Related Topics
Life Sciences
Neuroscience
Sensory Systems
Authors
Aasef G. Shaikh, Paul G. Finlayson,