Ethanol increases HSP70 concentrations in honeybee (Apis mellifera L.) brain tissue.
Previous research on the honeybee ethanol model established how acute ethanol exposure altered function at different levels of organization: behavior and learning, ecology, and physiology. The purpose of this study was to evaluate whether ethanol doses that affect honeybee behavior also induce a significant stress response, measured by heat shock protein 70 (HSP70) concentrations, in honeybee brain tissues. Experiment 1 examined how pretreatment handling influenced brain HSP70 concentrations in three pretreatment groups of bees; immediately after being collected, after being harnessed and fed, and after 22-24h in a harness. HSP70 concentrations did not differ among pretreatment groups within replicates, although we observed significantly different HSP70 concentrations between the two replicates. Experiment 2 investigated the relationship between ethanol dose and brain HSP70 concentrations. Bees were placed in seven experimental groups, the three pretreatment groups as in Experiment 1 and four ethanol-fed groups. Bees in ethanol treatments were fed 1.5M sucrose (control) and 1.5M sucrose-ethanol solutions containing 2.5, 5, and 10% ethanol, allowed to sit for 4h, and dissected brains were assayed for HSP70. We observed ethanol-induced increases in honeybee brain HSP70 concentrations from the control group through the 5% ethanol group. Only bees in the 5% ethanol group had HSP70 concentrations significantly higher than the control group. The inverted U-shaped ethanol dose-HSP70 concentration response curve indicated that ingestion of 2.5% ethanol and 5% ethanol stimulated the stress response, whereas ingestion of 10% ethanol inhibited the stress response. Doses that show maximum HSP70 concentration (5% ethanol) or HSP70 inhibition (10% ethanol) correspond to those (> or =5% ethanol) that also impaired honeybees in previous studies. We conclude that acute ethanol intoxication by solutions containing > or =5% ethanol causes significant ethanol-induced stress in brain tissue that impairs honeybee behavior and associative learning.
Hranitz
John M
JM
Department of Biological and Allied Health Sciences, Bloomsburg University of Pennsylvania, 17815, USA. jhranitz@bloomu.edu
Abramson
Charles I
CI
Carter
Richard P
RP
D000818:Animals; D001516:Bees / Q000187:drug effects* / Q000378:metabolism; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000008:administration & dosage / Q000494:pharmacology*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D023421:Models, Animal; D013312:Stress, Physiological; D013395:Sucrose / Q000008:administration & dosage
D018840:HSP70 Heat-Shock Proteins; D000431:Ethanol; D013395:Sucrose