Chilling-injury and disturbance of ion homeostasis in the coxal muscle of the tropical cockroach (Nauphoeta cinerea)

Comp Biochem Physiol B Biochem Mol Biol. 2006 Feb;143(2):171-9. doi: 10.1016/j.cbpb.2005.11.005. Epub 2005 Dec 20.

Abstract

Adults of warm- and cold-acclimated tropical cockroaches, Nauphoeta cinerea were exposed to low temperatures of 0 or 5 degrees C for various time intervals (hours to days). Development of chilling-injury (defects in crawling and uncoordinated movements) and mortality during the exposure were assessed and correlated with the changes in concentrations of metal ions (Na(+), K(+) and Mg(2+)) in the haemolymph and coxal muscle tissue. Warm-acclimated insects entered chill-coma at both low temperatures. In their haemolymph, the [Na(+)] and [Mg(2+)] linearly decreased and [K(+)] increased with the increasing time of exposure. The rate of concentration changes was higher at 0 than at 5 degrees C. The concentration changes resulted in gradually dissipating equilibrium potentials across the muscle cell membranes. For instance, E(K) decreased from -49.8 to -20.7 mV during 7 days at 5 degrees C. Such a disturbance of ion homeostasis was paralleled by the gradual development of chilling-injury and mortality. Most of the cockroaches showed chilling-injury when the molar ratio of [Na(+)]/[K(+)] in their haemolymph decreased from an initial of 4.4 to 2.1-2.5. In contrast, the cold-acclimated cockroaches did not enter chill-coma. They maintained constant concentrations of ions in their haemolymph, constant equilibrium potentials across muscle cell membranes and the development of chilling-injury was significantly suppressed at 5 degrees C for 7 days.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acclimatization*
  • Animals
  • Cell Membrane / physiology
  • Cockroaches / metabolism*
  • Cold Temperature*
  • Homeostasis
  • Membrane Potentials / physiology
  • Metals*
  • Muscle, Skeletal / cytology
  • Muscle, Skeletal / physiology*

Substances

  • Metals