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The effects of rapid eye movement sleep restriction (REMSR) in rats during late pregnancy were studied on the ultrasonic vocalizations (USVs) made by the pups. USVs are distress calls inaudible to human ears. Rapid eye movement (REM) sleep was restricted in one group of pregnant rats for 22 hours, starting from gestational day 14 to 20, using standard single platform method. The USVs of male pups were recorded after a brief isolation from their mother for two minutes on alternate post-natal days, from day one till weaning. The USVs were recorded using microphones and were analysed qualitatively and quantitatively using SASPro software. Control pups produced maximum vocalization on post-natal days 9 to 11. In comparison, the pups born to REMSR mothers showed not only a reduction in vocalization but also a delay in peak call making days. The experimental group showed variations in the types and characteristics of call types, and alteration in temporal profile. The blunting of distress call making response in these pups indicates that maternal sleep plays a role in regulating the neural development involved in vocalizations and possibly in shaping the emotional behaviour in neonates. It is suggested that the reduced ultrasonic vocalizations can be utilized as a reliable early marker for affective state in rat pups. Such impaired vocalization responses could provide an important lead in understanding mother-child bonding for an optimal cognitive development during post-partum life. This is the first report showing a potential link between maternal REM sleep deprivation and the vocalization in neonates and infants.

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Background: Outcomes of neurobehavioral studies are invariably affected by the variations in the anxiety traits of animals in the same species. Identifying those traits and categorizing them accordingly would improve the reproducibility of results, and reduce the variation in the results from different laboratories. Purpose: The present study was done to identify the possible groups among the normal population of outbred adult male Wistar rats. Methods: Anxiety traits were measured in elevated plus maze (EPM) test and open field test (OFT). The various anxiety responses from these tests were subjected to exploratory factor and hierarchical cluster analyses. Different clusters thus derived were compared with each other. Results and Conclusion: In exploratory factorial analysis, 2 components, that is, anxiety and activity were derived from the EPM and OFT parameters. Cluster analysis of EPM parameters classified the rats into 3 groups “high anxiety and low activity”, “medium anxiety and high activity”, and “low anxiety and medium activity”. Whereas, cluster analysis on OFT parameters identified one more group namely “low anxiety and high activity”. The rats which came under the clusters formed from the EPM and OFT parameters were not identical. Moreover, EPM and OFT may be measuring different aspects of anxiety.

Background and Aims:Sound knowledge about effect site concentration (Ce) of propofol aids in smooth induction, maintenance and early recovery. We studied the correlation between Ce of propofol at loss of response to verbal command and recovery concentration using target-controlled infusion (TCI) in Indian patients who underwent spine surgeries.Methods:Ninety patients undergoing spine surgeries were included. Total intravenous anaesthesia (TIVA) technique with TCI for propofol using modified Marsh model was used. Entropy and neuromuscular transmission were used. Ce at induction and recovery and the corresponding state entropy (SE) values were noted.Results:The mean propofol Ce and SE at induction were 2.34 ± 0.24 μg/ml and 52 ± 8, respectively. The mean propofol Ce and SE at recovery were 1.02 ± 0.22 μg/ml and 86.80 ± 2.86, respectively. The Ce at recovery was approximately 50% of the induction value. The correlation coefficient 'r' between Ce at induction and recovery was 0.56. The mean infusion dose of propofol during the maintenance period was 81 ± 14.33 μg/kg/min. The average induction dose of propofol was 1.17 ± 0.2 mg/kg.Conclusion:There is a positive correlation between Ce at induction and recovery. Ce for recovery may have to be set at a lower level during TCI-TIVA and appropriately infusion should be stopped for early recovery. The induction and maintenance doses of propofol are lower than the recommended doses. Data emphasise the need for pharmacokinetic model based on our population characteristics.

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