2-NAP, a peripheral CCK-A receptor antagonist, modulates the development of a preference for the mother by the newborn lamb.
The aim of this study was to investigate the effect of devazepide (DEV), a cholecystokinin (CCK)-A receptor antagonist, which crosses the blood-brain barrier (BBB) and prevents the development of a preferential relationship with the dam, and compare it to that of 2-NAP, which acts peripherally. At birth, lambs received either an intraperitoneal injection of saline (CTL), DEV (0.1 mg/kg), or 2-NAP (0.01, 0.1, or 1 mg/kg). No major side effects were observed after the injection, however, there was a trend for lambs receiving CCK-A antagonists to be more vocal in the first 2 h and to loose more weight between birth and 3 h. When tested in a two-choice test situations at 24 h of age, the latency to reach a ewe and the total time spent next to them were not affected by the treatments. On the other hand, unlike CTLs, lambs receiving DEV or 0.1 mg of 2-NAP did not spend significantly more time near their dam than near the alien ewe. 2-NAP had no effect at 0.01 mg/kg, but at 1 mg/kg, it improved the preference score. There was no relationship between preference scores and the variations in weight recorded during the neonatal period. The effects of DEV, but not those of 2-NAP, persisted at 48 h of age. Thus, these results support the hypothesis that peripheral CCK receptors are involved in the development of a preference for the mother, but the effects differ according to the amount of 2-NAP that the lambs receive.
Goursaud
A P
AP
Equipe de Comportement Animal, CNRS/INRA URA 1291, Unité de Physiologie de la Reproduction et des Comportements, 37380 Nouzilly, France.
Nowak
R
R
D000818:Animals; D000831:Animals, Newborn; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D020109:Devazepide / Q000494:pharmacology*; D005260:Female; D006727:Hormone Antagonists / Q000494:pharmacology*; D009035:Mothers; D009282:Naphthalenesulfonates / Q000494:pharmacology*; D009769:Object Attachment; D011247:Pregnancy; D043886:Receptor, Cholecystokinin A; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors* / Q000502:physiology; D012756:Sheep; D014828:Vocalization, Animal / Q000187:drug effects / Q000502:physiology
D006727:Hormone Antagonists; D009282:Naphthalenesulfonates; D043886:Receptor, Cholecystokinin A; D011949:Receptors, Cholecystokinin; C080661:N-(2-naphthalenesulfonyl)aspartyl-(2-phenethyl)amide; D001224:Aspartic Acid; D020109:Devazepide