Temperature dependence of cardiac sarcoplasmic reticulum and sarcolemma in the ventricle of catfish (Clarias gariepinus)

Abstract

The present study was undertaken to examine the relative contribution of the SR-Ca 2+ release and sarcolemmal Ca 2+ channels in developing the cardiac force at two different temperatures (20 and 30°C) in the catfish (Clarias gariepinus).The sarcolemmal Ca 2+ contribution of activator Ca 2+ was greater at a test temperature of 30°C as assessed by verapamil. Whereas the SR-Ca 2+ contribution was higher at 20 and 30°C and a frequency rate of 0.2 and 0.4 Hz as assessed by caffeine and adrenaline, respectively. Bradykinin potentiating factor (BPF 7 ) which was isolated from jelly fish (Cassiopea andromeda) decreased the cardiac force developed at a frequency rate of 0.2 Hz and a temperature of 20°C, whereas it increased the force developed at frequency rates of 0.2 and 0.4 Hz at 30°C. These results indicate that BPF 7 may act like verapamil in reducing the cardiac force through blocking the sarcolemmal Ca 2+ channels at low temperature and like adrenaline in an increase of the cardiac force developed at warm temperature and the high frequency rate through stimulation of SR-Ca 2+ activator. Therefore, this study indicates that the sarcolemmal Ca 2+ influx and the SR-Ca 2+ release contributors of activator Ca 2+ for cardiac force development in the catfish heart were significantly greater at warm temperature and at the pacing frequency rates of 0.2 and 0.4 Hz as assessed by verapamil, adrenaline, caffeine and BPF 7 . However, the relative contribution of the sarcolemmal Ca 2+ influx in the development of cardiac force in the catfish heart was greater than that of SR-Ca 2+ release. ª 2015 The Egyptian German Society for Zoology. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Excitation-contraction coupling and its relation to synaptic dysfunction in Drosophila

“…Our results also found that the strength of muscle contractions increases with decreases in temperature, saturating at 17-18°C. In addition, to the effects on axonal conduction properties, temperature may also affect multiple aspects of muscle contraction from membrane excitation (Vornanen, 2016), Ca 2+- dynamics from the SR (Abu-Amra et al, 2015; Shiels et al, 2002), Ca 2+ -dependent contraction activation (Ranatunga, 2018), and mechanisms of cross-bridge cycling (Wang and Kawai, 2001). While effects of temperature on synaptic efficacy appear to directly translate to the excitation-contraction coupling machinery, it is possible that temperature is also affecting multiple aspects of muscle biology.…”

Comparative ameliorative actions of extracted bradykinin potentiating fraction from cobra snake venom and synthetic antioxidants on hepatic tissue of aflatoxicosed rats

“…Dugyala and Sharma (1996), Batey and Wang (2002) and Miao et al (2016) claimed that cellular components of the immune system which produce various cytokines play a key role in host resistance against intoxicating inflammatory actions. The tested isolated snake venom peptide BPF (GII 2 ) (ACE inhibitor) that potentiates the endogenous BK via activation of B 2 receptors; significantly increased the cytokine IL-1β against induced aflatoxicosis (Murakami et al 1997;Fernandes et al 2001;Abu-Amra et al 2015). The authors recorded a profound cell signalling that initiated gene expression for TNFα, phospho-lipase A 2 and other pro-inflammatory immune response by such activated bradykinin.…”