Ketamine blocks a taste recognition memory in fetal rats
Section snippets
Subject
The subjects were perinatal Sprague–Dawley rats (male and female) obtained from timed-pregnant female rats supplied by Zivic-Miller Laboratories (Zelienople, PA). The date of conception (i.e., the first day that a vaginal plug was detected) was designated as “embryonic day 0” (E0). Pregnant animals (from which our subjects were derived) were individually housed in plastic “shoe box” cages (44.45 cm long×21.59 cm wide×20.32 cm high). Home cage temperature was maintained at 23–26°C under a
Results
The current data indicate that perinatal rats can discriminate between a novel and familiar taste. On P3, control rats (i.e., those that did not receive ketamine on E19) previously treated with SAC, exhibited significantly more mouth movements and licks than rats previously treated with water on E19 (see Fig. 1). Similarly, perseverative mouth movements were much more prominent in neonates tasting familiar SAC (see Fig. 2). The ANOVA of the mouthing and licking data revealed a significant SAC
Discussion
The data presented here indicate that P3 neonatal rats exhibited different orofacial movements depending on whether the taste of SAC was novel or familiar. The frequency of mouthing and licking responses is enhanced following lavage with familiar SAC and relatively suppressed after novel SAC. Ketamine administered before the initial taste manipulation (on E19) significantly reduced the differential response to novel vs. familiar SAC 5 days later.
The behaviors associated with this taste
Acknowledgements
The authors wish to thank David Revta and William Liggett for their assistance in building the neonatal testing unit. The following students and colleagues at Baldwin-Wallace College provided excellent technical support in these studies: Amy Booth, Kathryn Bryan, April Carter, Christine Dengler, Dominic Donnellan, Ben Girdler, Cynthia Kenmuir, Nadia Lelutiu, Colleen McMullen, Lora Pagel, Anaibelith Perez, Kristie Randall, Louie Rundo, Erin Simon, Tennille Lewis, Melissa Vanderkaay, Jessica
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