Ex demerol activate natural g protein coupled

Info icon This preview shows pages 21–23. Sign up to view the full content.

View Full Document Right Arrow Icon
Ex: Demerol Activate natural G-protein coupled receptors for endorphins (nature’s pain relievers) in the brain. endorphin concentration is usually extremely low Runners high = run to an extent that your body releases endorphins to help your body deal with the pain In order to release endorphins, there has to be new pain introduced Endorphins are released in very small amounts Triggers receptor downregulation, as well as desensitization resulting from functional uncoupling of G-protein receptors to their effector molecule o Opioid receptor downregulation Got a really strong high Cells respond immediately and cells take away some of these receptors so don’t get such an intense high Have to keep increasing the dosage to get the same high as the very first intense high Can overdose from this including heroin; this can also happen with alcohol o Nicotine Addiction Nicotine has an extremely high affinity (very strong attraction) for acetylcholine receptors in the brain. it essentially out-competes acetylcholine for these receptors Calls that require acetylcholine for signaling respond by making more acetylcholine receptors, and releasing much more acetylcholine Nicotine becomes addicting when introduced with all the other toxins in a cigarette; nicotine alone is not addicting Upregulation of receptors by nicotine If there are not enough nicotine around, the cell responds by making more receptors, meaning need more nicotine There is also evidence that increased use of nicotine results in increased ability of an individual to metabolize nicotine. Results in a shorter half-life of the drug It has also been suggested that nicotine upregulates extracellular mechanisms for degrading the drug o Mechanisms for Drug Tolerance Pharmacokinetic tolerance : the result of lower concentrations of a drug actually reaching the receptor. Could be caused by degradation, or increased metabolism of the drug (nicotine) Pharmacodynamics tolerance : cellular mechanism that results in receptor downregulation (opiates) or Upregulation (nicotine) Drug addiction alters your baseline; if you start taking drugs every day, you brain gets an increased baseline; when you stop taking that drug, your brain isn’t responding the way it was when you were taking the drugs and can cause withdrawal symptoms >> aka it’s an addictive drug - Effect of receptor affinity on receptor-ligand binding o Affinity place a huge role when there is a low concentration o At low concentration, the only one that will bind to a receptor is the one with a high affinity o At high concentration, they will both bind all the receptors - Ligand Properties o Agonist: ligands that bind to receptors and cause a biological response
Image of page 21

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
22 o Antagonist: ligands that bind to receptors and do not cause a biological response Antagonists may compete with agonists and decrease agonists binding and cellular response - Signal transduction o
Image of page 22
Image of page 23
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern