Norepinephrine and associative conditioning in the neonatal rat somatosensory system.
Neonatal rats, aged postnatal days 3-4, were trained in a somatosensory associative conditioning task involving temporal correlation of facial vibrissa stimulation and aversive shock. This training resulted in a subsequent conditioned behavioral activation/arousal response to vibrissa stimulation alone, compared to non-learning control pups trained with random vibrissa-shock presentations. The acquisition of the conditioned response was blocked by systemic injections of the NE beta-receptor antagonist propranolol in a dose-dependent manner. In a second study, vibrissa stimulation was paired with systemic injections of the NE beta-receptor agonist isoproterenol. Association of vibrissa stimulation with beta-receptor activation resulted in subsequent conditioned responses to vibrissa stimulation alone, in a dose-dependent manner. Together, these results suggest that early associative somatosensory conditioning requires and involves NE in a manner similar to that previously demonstrated for early olfactory learning.
D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001143:Arousal; D001245:Association Learning / Q000187:drug effects / Q000502:physiology*; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology*; D004597:Electroshock; D007545:Isoproterenol / Q000494:pharmacology*; D009638:Norepinephrine / Q000502:physiology*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D020318:Rats, Long-Evans; D014738:Vibrissae / Q000294:innervation