title: Lipopolysaccharide does not affect acoustic startle reflex in mice.
abstract: Bacterial endotoxin (lipopolysaccharide; LPS) evokes in rodents an adaptive sickness behavior. It also produces changes in stress hormones secretion and activity of brain serotonergic and noradrenergic systems that have been implicated in stress responses, fear, and anxiety. Acoustic startle reflex (ASR) is regarded as a protective behavioral response that is enhanced in threatening situations or following an aversive event, and it can be modulated by physiological and emotional state of an animal. Effects of intraperitoneal injections of LPS on ASR, prepulse inhibition (PPI), locomotor activity in open field, and blood plasma corticosterone concentration were studied in lines of mice that display high (HA line) or low (LA line) swim stress-induced analgesia and also differ in emotional behaviors, including the magnitude of ASR. In both lines LPS produced robust sickness behavior, as evidenced by a decrease in locomotion and body weight, and an increase in corticosterone concentration. However, in neither line LPS injections affected responses to acoustic stimuli as assessed by the ASR and PPI magnitudes. The findings suggest that in sickness behavior induced by LPS the protective responses to salient environmental stimuli are not impaired. The significance of this finding for the concept of sickness behavior is discussed.
authors.affiliation: Department of Animal Behavior, Institute of Genetics and Animal Breeding, Polish Academy of Sciences, Jastrzebiec, Poland.
authors.forename: Grzegorz R
authors.initials: GR
authors.lastname: Juszczak
authors.forename: Janusz
authors.initials: J
authors.lastname: Blaszczyk
authors.forename: Bogdan
authors.initials: B
authors.lastname: Sadowski
authors.forename: Adam T
authors.initials: AT
authors.lastname: Sliwa
authors.forename: Patrycja
authors.initials: P
authors.lastname: Wolak
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Tymosiak-Zielinska
authors.forename: Pawel
authors.initials: P
authors.lastname: Lisowski
authors.forename: Artur H
authors.initials: AH
authors.lastname: Swiergiel
mesh_terms: D000161:Acoustic Stimulation; D000698:Analgesia; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D003345:Corticosterone / Q000097:blood; D016291:Dizocilpine Maleate / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D007274:Injections, Intraperitoneal; D008070:Lipopolysaccharides / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009043:Motor Activity / Q000187:drug effects; D013216:Reflex, Startle / Q000187:drug effects*; D012803:Sick Role; D013312:Stress, Physiological / Q000209:etiology; D013550:Swimming
chemical_list: D018691:Excitatory Amino Acid Antagonists; D008070:Lipopolysaccharides; D016291:Dizocilpine Maleate; D003345:Corticosterone