Abstract
The effect of oxygen at high pressure (OHP) on resting membrane properties (effective membrane resistance (Reff) and membrane potential (Vm)) and the spontaneous release of excitatory transmitter were examined at the lobster neuromuscular junction. Pressurization with 100% oxygen to 150 pounds per square inch gauge pressure (psig) or with nitrogen to 150 psig (7,000 mmHg nitrogen and 135 mmHg oxygen) produced a decrease in Reff associated with a hyperpolarization of Vm. These changes, however, returned to control values within 20--30 min after completion of pressurization. Spontaneous release of excitatory transmitter was shown to increase dramatically in the presence of 100% oxygen at 150 psig. The increase in miniature end-plate potential (MEPP) frequency persisted beyond the transient changes seen with Reff and Vm. This effect was selective to oxygen, as pressurization with nitrogen did not produce an increase in MEPP frequency. No change in average MEPP amplitude was seen with either OHP or pressure alone. An OHP-induced increase in MEPP frequency was also seen at the frog neuromuscular junction. The results indicate that both glutamate-mediated and acetylcholine-mediated synaptic transmission are altered by OHP.
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.
