Ethanol increases HSP70 concentrations in honeybee ( Apis mellifera L.) brain tissue

• Published in: Alcohol (Fayetteville, N.Y.) Vol. 44; no. 3; pp. 275 - 282
• Main Authors: Hranitz, John M, Abramson, Charles I, Carter, Richard P
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-05-2010; Elsevier Limited
• Subjects: Animals; Apis mellifera; Bees - drug effects; Bees - metabolism; Behavior; Brain - drug effects; Brain - metabolism; Cell culture; Dose-Response Relationship, Drug; Enzymes; Ethanol; Ethanol - administration & dosage; Ethanol - pharmacology; Experiments; Foraging behavior; Heat shock proteins; Honeybee; HSP70; HSP70 Heat-Shock Proteins - genetics; HSP70 Heat-Shock Proteins - metabolism; Lipids; Metabolism; Models, Animal; Organisms; Oxidative stress; Proteins; Psychiatry; Stress; Stress response; Stress, Physiological; Studies; Sucrose - administration & dosage; Vertebrates; Apis mellifera; Honeybee; HSP70; Ethanol; Stress
• ISSN: 0741-8329; 1873-6823
• DOI: 10.1016/j.alcohol.2010.02.003

Abstract 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 22–24 h 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 1.5 M sucrose (control) and 1.5 M sucrose–ethanol solutions containing 2.5, 5, and 10% ethanol, allowed to sit for 4 h, 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 (≥5% ethanol) that also impaired honeybees in previous studies. We conclude that acute ethanol intoxication by solutions containing ≥5% ethanol causes significant ethanol-induced stress in brain tissue that impairs honeybee behavior and associative learning.