The biological effect of agonist on tissue can be investigated and quantified by obtaining a dose-response curve. The concentration (dose) of ligand that is required to obtain 50% of a maximum biological response can be deduced by this curve. This is known as the EC50 value. (Chen, D J A Wyllie and P E, 2007) The aim of this experiment was conduct an organ bath and test two agonists, Acetylcholine and 5 Hydroxytryptamine with tissue of a rat ileum in an attempt to explain the effects of an agonist on a rat ileum. Furthermore the effect of an antagonism on a rat ileum with the use of three antagonists was investigated in order to explain the various forms of antagonism involved in the interaction between an agonist and antagonist.
The tissue used in the organ bath was smooth muscle tissue of a rat ileum. Smooth muscle cells receive neural innervation from the autonomic nervous system. In addition, the contractile state of smooth muscle is regulated by hormones and other local chemical signals. Regardless of the stimulus, smooth muscle cells use cross-bridge cycling between actin and...
In the beginning phases of muscle contraction, a “cocked” motor neuron in the spinal cord is activated to form a neuromuscular junction with each muscle fiber when it begins branching out to each cell. An action potential is passed down the nerve, releasing calcium, which simultaneously stimulates the release of acetylcholine onto the sarcolemma. As long as calcium and ATP are present, the contraction will continue. Acetylcholine then initiates the resting potential’s change under the motor end plate, stimulates the action potential, and passes along both directions on the surface of the muscle fiber. Sodium ions rush into the cell through the open channels to depolarize the sarcolemma. The depolarization spreads. The potassium channels open while the sodium channels close off, which repolarizes the entire cell. The action potential is dispersed throughout the cell through the transverse tubule, causing the sarcoplasmic reticulum to release
Antiarrhythmic agents are used to suppress abnormal rhythms of the heart. Many attempts have been made to classify antiarrhythmic agents. There is a problem from the fact that many of the antiarrhythmic agents have multiple actions, making any classification accurate. Betapace (sotalol) comes in tablets and solution for oral a...
Parameters of CAL 1 were changed to zero grams and CAL 2 was changed to fifty grams. Nerve stimulation was induced for every fifteen seconds at an increment frequency of 0.5 pps (parts per second), 1.0 pps, 2.0 pps, 4.0 pps, 8.0 pps, 15 pps, and 25 pps. Every increment trial has a thirty-second waiting period. To witness the effects of tubocurare on muscle activity, the baseline was maintained between 20-30 grams and a control was established by turning the stimulator on repeat for 60-120 seconds. Then 0.25 ml of tubocurare was infused into the gastrocnemius muscle.
This paper discusses pharmacology and terminology related to “Pharmacology” which is the branch of medicine concerned with the uses, effects, and modes of action of drugs“ pharmacology. 2015. In Merriam-Webster.com. The study of different classes of drugs, routes of absorption, and drugs have effects on those consuming them. There are drugs that are necessary for illnesses and healing but, there are medicines that cause concern regarding interaction and harming the body.
VanPutte, C., Regan, J., & Russo, A. (2014). Seeley's anatomy & physiology(10th ed.). NEW YORK, NY: MCGRAW-HILL.
The second part of this lab was a computer simulation program to illustrate a frog’s electrocardiogram using various drugs in an isolated setting. The computer program entitled “Effects of Drugs on the Frog Heart” allowed experimental conditions to be set for specific drugs. The different drugs used were calcium, digitalis, pilocarpine, atropine, potassium, epinephrine, caffeine, and nicotine. Each of these drugs caused a different electrocardiogram and beats per minute reading. The calcium-magnesium ration affects “the permeability of the cell membrane”(Fox). When calcium is placed directly on the heart it results in three physiological functions. The force of the heart increases while the cardiac rate decreases. It also causes the appearance of “ectopic pacemakers in the ventricles, producing abnormal rhythms” (Fox). Digitalis’ affect on the heart is very similar to that of calcium. It inhibits the sodium-potassium pump activated by ATP that promotes the uptake of extracellular calcium by the heart. This in return strengthens myocardial contraction (Springhouse). Pilocarpine on the other hand
Simon, E. J., Reece, J. B., Dickey, J. L. (02/2012). Campbell Essential Biology with Physiology, 4th Edition [VitalSource Bookshelf version 6.2]. Retrieved from http://online.vitalsource.com/books/9781256902089
Comparison of the Effects of Antidepressants and Their Metabolites on Reuptake of Biogenic Amines and on Receptor Bindings. Cellular and Molecular Neurobiology, Vol.19, No.4.Denmark: Plenum Publishing Co. Science Direct, (2003).Fluoxetine inhibits A-type Potassium Currents in Primary Cultured Rat Hippocampal Neurons. Department of Physiology, Medical Research Center, South Korea.
Ross, A. C. (2005). Physiology. In B. Caballero, L. Allen, & A. Prentice (Eds.), Encyclopedia of
Neurotransmitters can also produce their effects by modulating the production of other signal-transducing molecules ("second messengers"messengers") in the post-synaptic cells (Cooper, Bloom and Roth 1996). Nine compounds -- belonging to three chemical families -- are generally believed to function as neurotransmitters somewhere in the central nervous system (CNS) or periphery. In addition, certain other body chemicals, for example adenosine, histamine, enkephalins, endorphins, and epinephrine, have neurotransmitter-like properties, and many additional true neurotransmitters may await discovery.
Try to imagine yourself, sitting at lunch, enjoying your sandwich and a few strawberries along the way. Once you are done your delicious meal, you take one last drink of orange juice and head to your next class. In a few minutes you are thinking about your upcoming visit to the mall. You've completely forgotten about that sandwich you had just ate. But it is still sitting in your stomach!! Now how does this work, how did your body absorb all that food? It all goes back to the digestive system.
...his is also part of a series called pharmacodynamics. This includes both the positive and negative changes brought on by a drug. This study is important because when a drug is administered it must reach the target in the organism before it is excreted or altered by the detoxifying enzymes in the body. Most of these enzymes are located in the liver. Results from these tests have allowed for synthesis of new drugs with better chemistries, distributions, and toxicity profiles.
6. McFadzean I and Gibson A (2002) “The developing relationship between receptor-operated and store-operated calcium channels in smooth muscle”. British Journal of Pharmacology 135: 1-13. Online, available at http://onlinelibrary.wiley.com/doi/10.1038/sj.bjp.0704468/pdf -Accessed 23/11/2013.
“Pharmacokinetics (PK) and pharmacodynamics (PD) can be seen as two sides of the same coin. PK and PD have a definite relationship, assessing how much drug gets to the site of action and then what that action is. Both activities are essential in the complete investigation of the interaction between the drug and body, and play significant roles in both drug development and their continual use in the clinical setting (Institute Of Clinical Research, Clinical Pharmacology Special Interest Group, Pharmacokinetics vs. Pharmacodynamics).”
The second aspect of this presentation was the 5-HT Receptor Antagonist. These antagonists are capable of decreasing the effect of NPY levels within the body. One antagonist, in particular, was shown to have a great effect on NPY effect, known as DOI. It was found that DOI blocks NYP responses inside the brain. One specific part of DOI was signaled out as being responsible for the blockage of NPY, known as 2A. Even though the DOI is able to decrease the sense of hunger, it is not used in humans because it causes very bad after effects, especially great nausea.