title: Strain-dependent effects of acute caffeine on anxiety-related behavior in PVG/c, Long-Evans and Wistar rats.
abstract: To assess the possibility that acute caffeine's behavioral action might depend on rats' strain, effects of 50mg/kg of the drug were observed on activity, anxiety-related behavior and habituation learning in male and female rats from three different strains, namely PVG/c, Long-Evans and Wistar. All subjects were tested in an open field, an elevated plus maze and a light-dark box. For the three strains combined, increased occupancy of the center of the open field and entries of the open plus-maze arms with caffeine suggested caffeine-induced anxiolysis, whereas increased grooming in the open field, decreased rearing in the plus maze and increased risk assessment in the light-dark box were consistent with anxiogenesis. Caffeine also reduced open-field rearing only for PVG/c rats, and entries into and occupation of the light side of the light-dark box only for Long-Evans rats, and increased total defecation in the three types of apparatus for all three strains combined. Overall, caffeine appeared to be mainly anxiogenic. The drug also increased open-field ambulation for PVG/c rats and walking for all rats, but decreased open-field ambulation and entries into the plus maze closed arms for Wistar rats alone. In general, Wistar rats appeared to be the least and Long-Evans the most anxious of the three strains investigated. Caffeine also decreased within-session habituation of open-field ambulation for PVG/c rats alone, thereby suggesting strain-dependent interference with non-associative learning and short-term memory. Several overall sex differences were also observed that supported female rats being more active and less anxious than males.
authors.affiliation: Department of Psychology, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand. Electronic address: rob.hughes@canterbury.ac.nz.
authors.forename: Robert N
authors.initials: RN
authors.lastname: Hughes
authors.affiliation: Department of Psychology, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand.
authors.forename: Nicola J
authors.initials: NJ
authors.lastname: Hancock
mesh_terms: D000818:Animals; D001007:Anxiety / Q000139:chemically induced / Q000523:psychology*; D001522:Behavior, Animal / Q000187:drug effects*; D002110:Caffeine / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003672:Defecation / Q000187:drug effects; D005106:Exploratory Behavior / Q000187:drug effects; D005260:Female; D006120:Grooming / Q000187:drug effects; D006185:Habituation, Psychophysiologic / Q000187:drug effects; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D051381:Rats; D020318:Rats, Long-Evans; D017208:Rats, Wistar; D012727:Sex Characteristics; D013045:Species Specificity
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine
keywords: Anxiety; Caffeine; Habituation; Memory; PVG/c Long–Evans Wistar rats; Sex differences