Postacquisition scopolamine treatments reveal the time course for the formation of lamb odor recognition memory in parturient ewes.
Institut National de Recherche Agronomique/Centre National de la Recherche Scientifique Within 4 hr after parturition, ewes learn to recognize the odor of their lamb. Whether scopolamine, a muscarinic antagonist, interferes with lamb odor retention was studied. After 4 hr of mother-young contact, ewes were separated from their lambs for 3 hr. During separation, they received intramuscular injections of saline, methylscopolamine (peripheral muscarinic antagonist), or scopolamine. Only scopolamine (100 microg/kg) prevented subsequent lamb recognition. To assess whether this effect depended on the duration of the learning phase, mothers remained with their lambs for 4, 8, or 16 hr before the 3-hr separation period and the scopolamine treatments. Ewes treated after 4 or 8 hr of contact displayed disturbed lamb recognition, whereas those having 16 hr of contact did not. Activation of central muscarinic receptors is therefore important for the formation of lamb odor recognition memory during a critical period of less than 16 hr postpartum.
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Laboratoire de Comportement Animal, Institut National de la Recherche Agronomique, Centre National de la Recherche Scientifique, Unité de Recherche Associée 1291, Nouzilly, France.
Gervais
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Durkin
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Lévy
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D000818:Animals; D001921:Brain / Q000187:drug effects; D005260:Female; D008425:Maternal Behavior / Q000187:drug effects*; D011939:Mental Recall / Q000187:drug effects*; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects*; D011976:Receptors, Muscarinic / Q000187:drug effects; D012601:Scopolamine / Q000494:pharmacology*; D012756:Sheep; D012903:Smell / Q000187:drug effects*; D013997:Time Factors
D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D012601:Scopolamine