title: Effect of isolation rearing on 5-HT agonist-induced responses in the rat.
abstract: Rats were reared from weaning (21 days of age) either in isolation or in social groups of five for 30 days and were then tested for spontaneous locomotor activity and 7 days later for 5-hydroxytryptamine (5-HT) agonist-induced behaviour. Isolation-reared animals displayed locomotor hyperactivity when placed in a novel environment. 5-methoxy-N,N-dimethyltryptamine (5-MeODMT) (2 mg/kg IP) and 8-hydroxy-2-(di-n-propyl-amino) tetralin (8-OH-DPAT) (0.32 mg/kg SC) elicited various components of the "5-HT behavioural syndrome" in both groups of animals, with forepaw treading and flat body posture being significantly more pronounced in isolation-reared animals. 1-(2,5-Dimethoxy-4-iodophenyl)-2-aminopropane (DOI) (2.5 mg/kg IP), a 5-HT2 selective agonist, produced a significantly greater number of back muscle contractions in isolation-reared animals but there was no difference between the two groups in the number of wet-dog shakes produced. Forepaw treading and flat body posture are thought to be mediated by 5-HT1A receptor activation, and stimulation of this receptor by either 5-MeODMT or 8-OH-DPAT produced greater responding in isolation-reared rats, suggesting supersensitivity of the post-synaptic 5-HT1A receptor. Wet-dog shakes are thought to be mediated by 5-HT2 and other (none-5-HT) receptors while back muscle contractions have been shown to be mediated by 5-HT2 receptors, indicating that there is also an increase in 5-HT2 receptor responsiveness in the socially-isolated animals.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham, UK.
authors.forename: I K
authors.initials: IK
authors.lastname: Wright
authors.forename: H
authors.initials: H
authors.lastname: Ismail
authors.forename: N
authors.initials: N
authors.lastname: Upton
authors.forename: C A
authors.initials: CA
authors.lastname: Marsden
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D000662:Amphetamines / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D008297:Male; D008732:Methoxydimethyltryptamines / Q000494:pharmacology; D009043:Motor Activity / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D051381:Rats; D011985:Receptors, Serotonin / Q000187:drug effects; D012701:Serotonin / Q000502:physiology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D012934:Social Isolation; D013764:Tetrahydronaphthalenes / Q000494:pharmacology
chemical_list: D000662:Amphetamines; D008732:Methoxydimethyltryptamines; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D013764:Tetrahydronaphthalenes; D012701:Serotonin; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; C015952:4-iodo-2,5-dimethoxyphenylisopropylamine