BIOM30001 Lecture Notes - Lecture 32: Orexin, Neuropeptide, Partial Agonist
Document Summary
S+: give a cue that signals availability of drug. Will animals reinstate alcohol-seeking following extinction & protracted abstinence? i) ii) Early reinstatement straight after extinction and animals relapsed. Yes, they do & ox1 receptors implicated at both time points. Relapse behaviour directed solely at the active leaver that gives them alcohol (not interested in lever that gives water) Orexin-containing neurons are activated during cue-induced reinstatement to alcohol- seeking. Black stain is fos, an oncogene - marker of neural activation. Produced in lateral hypothalamus, dorsal medial hypothalamus, perifornical region. Under s+ (alcohol cue condition) there is profound activation of these neurons but not s- Orexin neurons (blue) in lateral hypothalamus innervate ventral tegmental area, containing dopaminergic neurons which project to accumbens and prefrontal cortex. Vta and amygdala has ox1 and ox2 receptors. Ox1r antagonist acts at medial pfc and vta to reduce cue mediated relapse of alcohol seeking. After about 10 days they become dependent on ethanol vapour.
