Browsing by Author "Kumar, VM"

Now showing 1 - 13 of 13
  • Item
    Ambient temperature that induces maximum sleep in rats
    (PHYSIOLOGY & BEHAVIOR, 2009) Kumar, D; Mallick, HN; Kumar, VM
    Changes in sleep and body temperature in rats at ambient temperatures below and above the self-selected temperature zone, are lacking in literature. In this report, the temperature preferred by the rats was first assessed before studying the changes in their sleep and body temperature, when they were exposed to ambient temperatures ranging from 18 degrees C to 36 degrees C. The rats preferred to stay at 27 degrees C when they were allowed to select their own ambient temperature. but maximum sleep was recorded when the rats were maintained at 30 degrees C. The ambient temperature-related changes in rapid eye movement sleep and deep slow wave sleep followed a bell-shaped curve, with a maximum at 30 degrees C. Of all the sleep parameters, rapid eye movement sleep showed a more marked ambient temperature-related change. Ambient temperatures above 33 degrees C and below 24 degrees C produced a significant reduction in sleep. Increase in sleep at 30 degrees C was associated with a slight elevation in body temperature, but a steep increase in body temperature at very high ambient temperature was associated with a decrease in sleep. Decrease in sleep at ambient temperatures below 24 degrees C was not related to any significant decrease in body temperature. Though maximum sleep was recorded at 30 degrees C, the sleep regulatory and thermoregulatory systems were at a functional equilibrium at 27 degrees C. (C) 2009 Elsevier Inc. All rights reserved.
  • Item
    Bal Krishan Anand (1917-2007)
    (CURRENT SCIENCE, 2008) Kumar, VM
  • Item
    Glutamate microinjection at the medial preoptic area enhances slow wave sleep in rats
    (BEHAVIOURAL BRAIN RESEARCH, 2011) Kaushik, MK; Kumar, VM; Mallick, HN
    A large body of evidence has established the role of the medial preoptic area (mPOA) in regulation of slow wave sleep (SWS). Although the mPOA neurons contain excitatory neurotransmitter glutamate, its role in sleep-wakefulness is not known. In the present study microinjection of monosodium glutamate (40, 80 and 120 ng) into the mPOA augmented SWS. Earlier reports have shown enhancement of paradoxical sleep by glutamate in other brain areas. (C) 2010 Elsevier B.V. All rights reserved.
  • Item
    Glutamate microinjection in the medial septum of rats decreases paradoxical sleep and increases slow wave sleep
    (NEUROREPORT, 2012) Mukherjee, D; Kaushik, MK; Jaryal, AK; Kumar, VM; Mallick, HN
    The role of the medial septum in suppressing paradoxical sleep and promoting slow wave sleep was suggested on the basis of neurotoxic lesion studies. However, these conclusions need to be substantiated with further experiments, including chemical stimulation studies. In this report, the medial septum was stimulated in adult male rats by microinjection of L-glutamate. Sleep-wakefulness was electrophysiologically recorded, through chronically implanted electrodes, for 2 h before the injection and 4 h after the injection. There was a decrease in paradoxical sleep during the first hour and an increase in slow wave sleep during the second hour after the injection. The present findings not only supported the lesion studies but also showed that the major role of the medial septum is to suppress paradoxical sleep. NeuroReport 23:451-456 (C) 2012 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.
  • Item
    Increased ultrasonic vocalizations and risk-taking in rat pups of sleep-deprived dams
    (Physiol Behav., 2015-02) Gulia, KK; Patel, N; Kumar, VM
    Ultrasonic vocalizations (USVs) in rodent pups are analogous to cries in human babies. There is reduction in USVs in pups after experimental deprivation of rapid eye movement sleep of dams during pregnancy. However, the effects of total sleep deprivation on the USVs of newborns and their emotional development are not documented. Male pups born to the rats that underwent total sleep deprivation for 5h during the third trimester made higher vocalizations, when tested on early postnatal days (pnds) in an isolation-paradigm. Their anxiety-related behaviors during pnds 25-28, were tested using elevated plus maze (EPM). In comparison to the control pups, weanlings of sleep-deprived dams made increased entries into the open arms and higher mobility in the EPM. Enhanced distress calls during early pnds and reduction in risk assessment in weanlings indicate a link between the two behaviors. The USVs during ontogeny may provide early signals about altered emotional development.
  • Item
    Increased ultrasonic vocalizations and risk-taking in rat pups of sleep-deprived dams
    (Physiol Behav., 2015-01) Gulia, KK; Patel, N; Kumar, VM
    Ultrasonic vocalizations (USVs) in rodent pups are analogous to cries in human babies. There is reduction in USVs in pups after experimental deprivation of rapid eye movement sleep of dams during pregnancy. However, the effects of total sleep deprivation on the USVs of newborns and their emotional development are not documented. Male pups born to the rats that underwent total sleep deprivation for 5h during the third trimester made higher vocalizations, when tested on early postnatal days (pnds) in an isolation-paradigm. Their anxiety-related behaviors during pnds 25-28, were tested using elevated plus maze (EPM). In comparison to the control pups, weanlings of sleep-deprived dams made increased entries into the open arms and higher mobility in the EPM. Enhanced distress calls during early pnds and reduction in risk assessment in weanlings indicate a link between the two behaviors. The USVs during ontogeny may provide early signals about altered emotional development.
  • Item
    L-glutamate microinjection in the preoptic area increases brain and body temperature in freely moving rats
    (NEUROREPORT, 2014) Sengupta, T; Jaryal, AK; Kumar, VM; Mallick, HN
    The role of the preoptic area (POA) in thermoregulation is well documented. Microinjection of various neurotransmitters into the POA in rats has been shown to influence body temperature. Alhough there are reports showing changes in temperature on administration of l-glutamate into the POA, the role of this excitatory amino acid in thermoregulation has not been studied in unanaesthetized rats. In the present study, brain and body temperatures were recorded in freely moving adult male Wistar rats with K-type thermocouple implanted near the hypothalamus and temperature transmitter implanted inside the peritoneum. Recordings were performed 2 h preinjection and 4 h postinjection. l-glutamate (0.14 nM) microinjection into the POA induced long-lasting hyperthermia and reduced locomotor activity. The rats remained curled up and showed piloerection. l-glutamate-induced hyperthermia was attenuated by previous injection of the ionotropic l-glutamate receptor antagonist, kynurenate (0.11 nM). We propose that l-glutamate in the POA participates not only in heat production and conservation but also plays a role in interlinking sleep and thermoregulation. (C) 2013 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.
  • Item
    Perirhinal cortex lesions delay ejaculation in rats
    (BEHAVIOURAL BRAIN RESEARCH, 2008) Sharma, K; Gulia, KK; Kumar, VM; Mallick, HN
    Afferents from the perirhinal cortex (PRh) form a major input to the hippocampal formation, which is known to be involved in sexual behavior in rodents. But there is a lacuna in literature regarding the role of the PRh in sexual behavior. Bilateral neurotoxic lesions of the PRh delayed the ejaculation latency and prolonged the mean inter-intromission interval significantly, suggesting a facilitatory role of the PRh in male rat sex behavior. (c) 2007 Elsevier B.V. All rights reserved.
  • Item
    PREFACE
    (SLEEP AND BIOLOGICAL RHYTHMS, 2010) Kumar, VM
  • Item
    Sleep deprivation during late pregnancy produces hyperactivity and increased risk-taking behavior in offspring
    (Brain Research., 2015-01) Radhakrishnan, A; Aswathy, BS; Kumar, VM; Gulia, KK
    Sleep deprivation in women resulting from their modern lifestyle, especially during pregnancy, is a serious concern as it can affect the health of the newborn. Anxiety disorders and cognitive deficits in the offspring are also on the rise. However, experimental studies on the effects of sleep loss during pregnancy, on emotional development and cognitive function of the newborn, are scanty in literature. In the current study, female rats were sleep-deprived for 5h by gentle handling, during the 6 days of the third trimester (days 14-19 of pregnancy). The effects of this sleep deprivation on anxiety-related behaviors of pups during their peri-adolescence age were studied using elevated plus maze (EPM). In addition to body weights of dams and offspring, the maternal behavior was also monitored. The weanlings of sleep-deprived dams showed heightened risk-taking behavior as they made increased explorations into the open arms of EPM. They also showed higher mobility in comparison to the control group. Though the body weights of sleep-deprived dams were comparable to those of the control group, their newborns had lower birth weight. Nevertheless, these pups gained weight and reached the control group values during the initial post-natal week. But after weaning, their rate of growth was lower than that of the control group. This is the first report providing evidences for the role of sleep during late pregnancy in shaping the neuropsychological development in offspring.
  • Item
    Sleep is neither a passive nor an active phenomenon
    (SLEEP AND BIOLOGICAL RHYTHMS, 2010) Kumar, VM
    According to traditional belief, prolonged wakefulness during the day is followed by brain rest at night in the form of sleep. This passive theory of sleep was replaced by the active sleep genesis concept, mainly after the realization that brain activity is only slightly reduced during sleep. There is now growing evidence to suggest that sleep is auto-regulatory and that it is not necessary to attribute sleep genesis to either an active or a passive mechanism.
  • Item
    Sleep medicine education in India
    (SLEEP AND BIOLOGICAL RHYTHMS, 2016) Mallick, HN; Kumar, VM
    India is an ancient country with a vast population, diverse geography and culture. Although sleep medicine has been rapidly progressing during the last decade in the country, the ancient Indian literature is rich in descriptions of sleep physiology and the importance of sleep in life. In spite of rapid industrialization and the emergence of a modern 24/7 h society, knowledge about sleep and its disorders is lacking amongst the general public and doctors. A need is felt to raise the level of awareness of sleep to that of the level of nutrition and exercise. There is shortage of trained certified sleep specialists and technicians to meet the emerging demand. A need is felt to provide standardized sleep health care service. The role of professional sleep societies, industry, private enterprises and government agencies in promoting sleep medicine education in the country is emphasized. Vertical integration of education in sleep physiology and disorders, from school level to graduate and postgraduate medical education, is advocated. To create specialists in the discipline, horizontal integration with physiology, neurology, psychiatry and pulmonary medicine is a viable solution in this multidisciplinary subject. The government should recognize sleep as an important public health issue.
  • Item
    Sleep medicine in ayurveda
    (SLEEP MEDICINE REVIEWS, 2016) Kumar, VM; Gulia, KK