WHOLE MUSCLE CONTRACTIONNEUROMUSCULAR JUNCTION, EXCITATION-CONTRACTION COUPLING, SLIDING FILAMENT THEORY, CONTRACTURES AND CRAMPSSKELETAL MUSCLE ORGANIZATIONFUNCTIONS AND PROPERTIES OF SKELETAL MUSCLE TISSUEMODULE 7: SKELETAL MUSCLE
  • A Little Muscle Pharmacology
    • 7.4.8

    A Little Muscle Pharmacology

    At this point, you may be thinking, “how on earth did anyone figure out this stuff?” To answer this question you need to understand that scientists who study physiological processes often employ drugs. Yep, drugs! A drug that has the same effect as acetylcholine will result in all kinds of information about how something works. We use the terms agonist and antagonist when referring to drugs. A drug that has the same effect as the neurotransmitter (acetylcholine) would be considered an agonist. A drug that blocks the effect of the neurotransmitter is called an antagonist.

    https://upload.wikimedia.org/wikipedia/commons/8/87/Agonist_%26_Antagonist.jpg

    Agonist & Antagonist. Author: Dolleyj Site: https://books.byui.edu/-WEWT;

    License: CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons.

     

    Look at the table below of different drugs used in the study of muscle physiology and see if you can predict the effect the drug would have on a muscle.

    Class of Drug

    Example

    Method of Action

    Result on Muscle

    Neuromuscular blocker

    tubocurarine (chemical obtained from the bark of a South American plant, used as arrow poison); alpha bungarotoxin (snake poison), pancuronium (lethal injection drug)

    Acetylcholine receptor antagonist

    Flaccid paralysis

    Neuromuscular blocker

    Succinylcholine
    (a synthesized chemical, known as the “perfect poison” for murder)

    Acetylcholine receptor antagonist (initial depolarization but then blocks the receptor)

    Flaccid paralysis

    Neuromuscular junction

    Neostigmine
    (a synthesized chemical)

    Inhibits Acetylcholinesterase activity

    Spastic paralysis

    Contractility

    Salbutamol
    (a synthesized chemical also known as albuterol)

    Enhances SERCA pump activity

    Reduced contractility

    Contractility

    Caffeine (chemical found in seeds, nuts or leaves, used as an insecticide by the plants)

    Enhances Ca++ release at the sarcoplasmic reticulum

    Increased contractility

    Neuromuscular junction

    Botulism

    Blocks SNARE proteins

    Flaccid Paralysis

    Neuromuscular junction

    Latrotoxin (Black widow spider poison)

    SNARE protein agonist

    Spastic paralysis

    This content is provided to you freely by BYU-I Books.

    Access it online or download it at https://books.byui.edu/bio_264_anatomy_phy_I/748__a_little_muscle.