Browsing by Author "Jaryal, AK"

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    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.
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    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.