Olfactory bulb α2-adrenoceptor activation promotes rat pup odor-preference learning via a cAMP-independent mechanism.
In this study, three lines of evidence suggest a role for α(2)-adrenoreceptors in rat pup odor-preference learning: olfactory bulb infusions of the α(2)-antagonist, yohimbine, prevents learning; the α(2)-agonist, clonidine, paired with odor, induces learning; and subthreshold clonidine paired with subthreshold β-adrenoceptor activation also recruits learning. Increased mitral cell layer pCREB occurs with clonidine-infusion, but cAMP is not increased. Similar results using a GABAa-antagonist suggest that disinhibition may support clonidine-induced learning. We suggest that norepinephrine can act through multiple bulbar adrenoceptor subtypes to induce odor learning and that cAMP-dependent, as well as cAMP-independent, signals may act as unconditioned stimuli.
Biomedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3V6, Canada.
Amin M D
AM
Shakhawat
Carolyn W
CW
Harley
Qi
Q
Yuan
D000818:Animals; D003214:Conditioning, Classical / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism; D007858:Learning / Q000502:physiology*; D009812:Odorants; D009830:Olfactory Bulb / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011942:Receptors, Adrenergic, alpha / Q000378:metabolism*
D011942:Receptors, Adrenergic, alpha; D000242:Cyclic AMP