I am currently conducting experiments using organ baths with rat duodenum and ileum tissues. These experiments involve the administration of various drugs, including Fluoroacetate, Bethanechol, Carbachol, SNP, Guanethidine, and Atropine. Additionally, I am using Krebs solution continuously aerated with 95% O2 and 5% CO2, maintaining a temperature of 37 degrees Celsius. My research focuses on studying the contraction and relaxation movements of the intestines, particularly the effects of these drugs in combination with Electrical Field Stimulation (EFS) set at parameters of 2-16 Hz, 1 msec, and 100V.

One significant challenge I face is the prolonged duration of these experiments, which can last several hours. During this extended period, I have noticed that the tissue responses are not as consistent or satisfactory as I would like them to be. I am particularly concerned about the inability to achieve the typical relaxation response observed with SNP and, in some cases, even observing contraction responses with SNP.

I am seeking guidance on how to maintain normal contraction after suspending the tissues and ensure accurate and consistent responses with each drug application. I am also uncertain about the timing of cumulative drug applications, such as Bethanechol and SNP, in relation to EFS. Additionally, I would appreciate guidance on the optimal duration to wait during each phase of drug application. Unfortunately, I have been unable to find this specific information in my literature search. I would greatly appreciate any assistance or suggested sources and contacts that could provide further insight into these challenges.