A Comparative Study On The Effects Of Ethanol And Acetaldehyde On The Activities Of Nerve And Heart

It is known to all that alcohol drinking can cause many healthy problems to our life. The diseases in brain, heart and blood vessel are most frequent and serious induced by ethanol. Acetaldehyde is the intermediate product in the process of alcohol metabolism. Many scientists have focused on the function of alcohol, and a few studies on the effects of acetaldehyde also have been conducted. However, comparative researches on the effects of ethanol and acetaldehyde are still very rare. We chose the nerve and heart as the specimens in our research to investigate the differences between the effects of ethanol and acetaldehyde.The stimulus threshold, the maximal stimulus, the peak value of the compound action potential and the refractory period were measured on the toad' s sciatic nerves 30 seconds after adding ethanol or acetaldehyde of different concentra -tion with Ringer' s solution, by using the biological experimental system BL-420. Ethanol at the concentration of 86-515 mmol/L reduced the value of stimulus threshold, the maximal stimulus and the refractory period, but the peak value of the compound action potential increased. The similar results were achieved with acetaldehyde at the concentration of8. 5-42. 8 mmol/L, but when the concentration of ethanol increased to the level of 859-1 545 mmol/L, the value of stimulus threshold, the maximal stimulus increased and the peak value of the compound action potential decreased (still higher than the control group), and the refractory period lengthened. While, arousing the similar results to alcohol, the concentration of acetaldehyde was just at 85. 6-429mmol/ ? L. The function of the nerves would not be recoverable if the concentration was over 1. 5 or 0. 5 mol/L with ethanol or acetaldehyde, respectively.To investigate the effects of ethanol and acetaldehyde with different concentration on the heart of bullfrog in vitro, we measured the frequency and amplitude of the specimens with BL~420+. The results showed that all the concentration of ethanol could make a significant decrease on the heart rate and contraction amplitude. A lower concentration of acetaldehyde made the heart rate and contraction amplitude increase and a high concentration of acetaldehyde may lead to damages on hearts irreversibly.The conclusion was that the direct effects of acetaldehyde on the nerve and heart in vitro were stronger than that of alcohol, and the results implied that acetaldehyde may play animportant role in the function of drinking, especially in the process of disease in the system of brain, heart and blood vessel.