NISCAIR Online Periodicals Repository

Research Journals >
Indian Journal of Experimental Biology (IJEB) >
IJEB Vol.46 [2008] >
IJEB Vol.46(04) [April 2008] >

Title: Bradycardia induced by Mesobuthus tamulus scorpion venom involves muscarinic receptor-G-protein-coupled cell signaling pathways
Authors: Deshpande, Shripad B.
Kanoo, Sadhana
Alex, Anitha B.
Keywords: Cardiac dysrhythmia
Guanylyl cyclase
Indian red scorpion
Methylene blue
Pertussis toxin
Issue Date: Apr-2008
Publisher: CSIR
Abstract: Indian red scorpion (Mesobuthus tamulus; MBT) envenomation produces various cardio-respiratory abnormalities including cardiac dysrhythmias. The underlying cell signaling pathways for the cardiac dysrhythmias produced by MBT venom are not known. The present study was therefore conducted to delineate the second messenger signaling pathways involved in MBT venom-induced atrial rhythm changes. The effects of venom and various antagonists were examined on spontaneously beating rat right atrial preparations in vitro. The MBT-venom produced an increase (35%), a decrease (45%) and again an increase (50%) in rate at 0.03, 0.3 and 3.0 µg/ml of venom, respectively. On the other hand, force of contraction exhibited a concentration-dependent rise (up to 40%) at all concentrations of venom. Pretreatment with atropine (0.3 µM) blocked the decrease in atrial rate at 0.3 µg/ml concentration of venom while no such blockade was seen in force of contraction. Submaximal concentration of ACh (0.1 nM) decreased the atrial rate by 25%. In the presence of MBT venom (0.3 µg/ml), ACh-induced fall in atrial rate was enhanced. The venom-induced fall in atrial rate and augmentation of ACh response were blocked by pertussis toxin (PTx; a Gi-inhibitor) or methylene blue (a G-cyclase inhibitor). The results indicate that the decrease in atrial rate produced by venom is mediated muscarinic by receptors via Gi-guanylyl cyclase mediated cell signaling pathways.
Page(s): 229-233
ISSN: 0019-5189
Source:IJEB Vol.46(04) [April 2008]

Files in This Item:

File Description SizeFormat
IJEB 46(4) 229-233.pdf98.66 kBAdobe PDFView/Open
 Current Page Visits: 612 
Recommend this item


Online Submission of Articles |  NISCAIR Website |  National Knowledge Resources Consortium |  Contact us |  Feedback

Disclaimer: NISCAIR assumes no responsibility for the statements and opinions advanced by contributors. The editorial staff in its work of examining papers received for publication is helped, in an honorary capacity, by many distinguished engineers and scientists.

CC License Except where otherwise noted, the Articles on this site are licensed under Creative Commons License: CC Attribution-Noncommercial-No Derivative Works 2.5 India

Copyright © 2015 The Council of Scientific and Industrial Research, New Delhi. All rights reserved.

Powered by DSpace Copyright © 2002-2007 MIT and Hewlett-Packard | Compliant to OAI-PMH V 2.0

Home Page Total Visits: 167502 since 01-Sep-2015  Last updated on 28-Jun-2016Webmaster: