alexa Inhibition of mouse neuromuscular transmission and contractile function by okadaic acid and cantharidin.
Agri and Aquaculture

Agri and Aquaculture

Agrotechnology

Author(s): Hong SJ

Abstract Share this page

Abstract 1. Phosphorylations of cellular proteins modulate biological activities. The effects of okadaic acid (0.1 - 10 microM) and cantharidin (1 - 100 microM), inhibitors of protein phosphatases, on the synaptic transmission at the mouse neuromuscular junction were explored. 2. Both inhibitors almost completely depressed twitch forces elicited by electrical stimulation of diaphragm muscles (the IC(50)s for okadaic acid and cantharidin were 1.1+/-0.2 and 13+/-1 microM, n=5, respectively) and suppressed contractures evoked by high K(+) and ryanodine more than 70\%. Contractures caused by cardiotoxin, which destroys the integrity of sarcolemma, were not depressed. 3. Both okadaic acid (10 microM) and cantharidin (100 microM) depolarized muscle membranes from approximately -80 to approximately -60 mV in a partially reversible and tetrodotoxin-sensitive manner. The initial short-term enhancement of twitch responses (up to approximately 40\%) was correlated with the inhibitors-induced repetitive firings of muscle action potential. 4. Treatment with either agent resulted in nearly complete inhibitions of endplate potential (epp). The IC(50)s were 0.8+/-0.2 and 9+/-2 microM (n=5), respectively, for okadaic acid and cantharidin. On high frequency stimulation, the coefficient of epps was increased more than 10 fold and the extent of epp run-down during stimulations intensified from approximately 25 to approximately 75\%. Analyses of presynaptic quantal releases revealed decreases in epp quantal content and the immediately available vesicle pool. 5. The frequency of miniature epp was initially elevated up to 2 fold then suppressed down to approximately 30\%. The small reduction in the amplitude was antagonized when the membrane of endplate area was repolarized. 6. The data suggest that okadaic acid and cantharidin inhibit mobilizations of synaptic vesicles and depress Ca(2+) release from sarcoplasmic reticulum and that protein phosphatases participate in the modulation of motor function.
This article was published in Br J Pharmacol and referenced in Agrotechnology

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

Peer Reviewed Journals
 
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
 
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

Agri, Food, Aqua and Veterinary Science Journals

Dr. Krish

agrifoodaquavet@omicsonline.com

1-702-714-7001 Extn: 9040

Clinical and Biochemistry Journals

Datta A

clinical_biochem@omicsonline.com

1-702-714-7001Extn: 9037

Business & Management Journals

Ronald

business@omicsonline.com

1-702-714-7001Extn: 9042

Chemical Engineering and Chemistry Journals

Gabriel Shaw

chemicaleng_chemistry@omicsonline.com

1-702-714-7001 Extn: 9040

Earth & Environmental Sciences

Katie Wilson

environmentalsci@omicsonline.com

1-702-714-7001Extn: 9042

Engineering Journals

James Franklin

engineering@omicsonline.com

1-702-714-7001Extn: 9042

General Science and Health care Journals

Andrea Jason

generalsci_healthcare@omicsonline.com

1-702-714-7001Extn: 9043

Genetics and Molecular Biology Journals

Anna Melissa

genetics_molbio@omicsonline.com

1-702-714-7001 Extn: 9006

Immunology & Microbiology Journals

David Gorantl

immuno_microbio@omicsonline.com

1-702-714-7001Extn: 9014

Informatics Journals

Stephanie Skinner

omics@omicsonline.com

1-702-714-7001Extn: 9039

Material Sciences Journals

Rachle Green

materialsci@omicsonline.com

1-702-714-7001Extn: 9039

Mathematics and Physics Journals

Jim Willison

mathematics_physics@omicsonline.com

1-702-714-7001 Extn: 9042

Medical Journals

Nimmi Anna

medical@omicsonline.com

1-702-714-7001 Extn: 9038

Neuroscience & Psychology Journals

Nathan T

neuro_psychology@omicsonline.com

1-702-714-7001Extn: 9041

Pharmaceutical Sciences Journals

John Behannon

pharma@omicsonline.com

1-702-714-7001Extn: 9007

Social & Political Science Journals

Steve Harry

social_politicalsci@omicsonline.com

1-702-714-7001 Extn: 9042

 
© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version