Abstract
Electrophysiological properties of guinea pig ambiguus (AMB) neurons were studied in a brainstem slice preparation. During subthreshold depolarization AMB neurons displayed an early slow depolarization and a late outward rectification both of which were blocked by replacing Ca 2+ with Co 2+ in the extracellular solution. AMB neurons showed hyperpolarizing inward rectification which was blocked by extracellular Cs + and is likely caused by the activation of Ih. In 58% ( n = 49) of AMB neurons spike firing was restricted to the early phase of a long-lasting depolarizing current injection (phasic firing). The remaining AMB neurons showed repetitive firing throughout the depolarization (tonic firing). A Ca 2+-mediated K + current ( I K(Ca)) caused an afterhyperpolarization that followed both single and repetitive spike firing. I K(Ca) also controlled the firing pattern in both types of firing, especially in the phasic firing. Norepinephrine (NE) blocked both the hyperpolarizing inward rectification and the Ca 2+-dependent AHP. These effects of NE were antagonized by propranolol. It is proposed that the blockade of I K(Ca) and Ih contribute to the improvement of the ‘signal-to-noise ratio’ by NE in AMB neurons.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
