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Query: UMLS:C0085593 (
chills
)
4,268
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
When insects are cooled, they initially lose their ability to perform coordinated movements at their critical thermal minima (CT
min
). At a slightly lower temperature, they enter a state of complete paralysis (
chill
coma onset temperature - CCO) and if they are returned to permissive temperatures they regain function after a recovery period which is termed
chill
coma recovery time (CCRT). These three phenotypes (CT
min
, CCO, and CCRT) are all popular measures of insect cold tolerance and it is therefore important to characterize the physiological processes that are responsible for these phenotypes. In the present study we measured extracellular field potentials in the central nervous system (CNS) and muscle membrane potential (V
m
) during cooling and recovery in three Drosophila species that have different cold tolerances. With these measurements we assess the role of the CNS and muscle V
m
in setting the lower thermal limits (CT
min
and CCO) and in delaying
chill
coma recovery (CCRT). The experiments suggest that entry into
chill
coma is primarily caused by the onset of a spreading depolarization in the CNS for all three species. In the two most cold-sensitive species we observed that the loss of CNS function was followed closely by a depolarization of muscle V
m
which is known to compromise muscle function. When flies are returned to benign temperature after a cold exposure we observe a rapid recovery of CNS function, but
functional recovery
was delayed by a slower recovery of muscle polarization. Thus, we demonstrate the primacy of different physiological systems (CNS vs. muscle) as determinants of the most commonly used cold tolerance measures for insects (CT
min
vs. CCRT).
...
PMID:The central nervous system and muscular system play different roles for chill coma onset and recovery in insects. 3091 Jun 13
