The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP), 1998
Light is involved in providing entrainment of circadian rhythms and the suppression of the pineal... more Light is involved in providing entrainment of circadian rhythms and the suppression of the pineal hormone melatonin. In patients with affective disorders, there have been indications of circadian as well as seasonal variation in illness, which may be reflected in melatonin production. Varying sensitivity to light has been noted within healthy individuals as well as in some patients with affective disorders. Recent evidence suggests that patients with panic disorder may have an altered and phase-delayed melatonin rhythm. The present study examined the nocturnal plasma melatonin rhythm in patients with panic disorder, and also examined their melatonin sensitivity to dim light. The melatonin rhythm was examined in 6 patients with panic disorder and 8 controls. The melatonin sensitivity to dim white light (200 lx) was examined in 8 patients with panic disorder and 63 controls and was compared to that of a group of 7 patients with other anxiety disorders. Patients with panic disorder dem...
... Letter to the Editor. Cholinergic modulation of cognitive function in healthy subjects: acute... more ... Letter to the Editor. Cholinergic modulation of cognitive function in healthy subjects: acute effects of donepezil, a cholinesterase inhibitor. Pradeep J. Nathan PhD 1,* ,; Allison Baker 2 ,; Elaine Carr 2 ,; Jemima Earle 2 ,; Meaghan Jones 2 ,; Michelle Nieciecki 2 ,; Chris Hutchison 2 ...
The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP), 2012
In Alzheimer's disease (AD), progressive accumulation of β-amyloid (Aβ) peptides impairs nico... more In Alzheimer's disease (AD), progressive accumulation of β-amyloid (Aβ) peptides impairs nicotinic acetylcholine receptor (nAChR) function by a mechanism that may involve α7 and α4β2-nAChR subtypes. Additionally, the beta-site amyloid precursor protein (APP)-cleaving enzyme (BACE), the rate-limiting enzyme in the pathogenic Aβ production pathway, is expressed at high levels in hippocampal and cortical regions of AD brains. We measured hippocampal area CA1 protein levels of BACE and α7- and α4β2-nAChR subunits using an Aβ rat model of AD (14-d osmotic pump i.c.v. infusion of 300 pmol/d Aβ peptides) in the presence and absence of chronic stress and/or chronic nicotine treatment. There was a significant increase in the levels of BACE in Aβ-infused rats, which were markedly intensified by chronic (4-6 wk) stress, but were normalized in Aβ rats chronically treated with nicotine (1 mg/kg b.i.d.). The levels of the three subunits α7, α4 and β2 were significantly decreased in Aβ rats, b...
Estrogen may be involved in schizophrenia by inhibiting serotonin-1A (5-HT(1A)) receptor function... more Estrogen may be involved in schizophrenia by inhibiting serotonin-1A (5-HT(1A)) receptor function. We examined the effects of estrogen pre-treatment on modulation of loudness dependence of the auditory evoked potential (LDAEP) and mismatch negativity by the 5-HT(1A) receptor partial agonist, buspirone. Using a double-blind, placebo-controlled, repeated-measures design in healthy female volunteers, we observed that buspirone treatment significantly increased LDAEP slope. Estrogen increased LDAEP slope on its own, and a further LDAEP increase by buspirone was not seen after estrogen pre-treatment. Similar results were observed for mismatch negativity, where buspirone caused a small increase of latency, although not amplitude, after placebo but not estrogen pre-treatment, which enhanced mismatch negativity latency on its own. These results are in line with our previous findings on prepulse inhibition showing an inhibitory effect of estrogen on the action of buspirone. Taken together, these data suggest that estrogen may inhibit 5-HT(1A) receptor-mediated disruptions of auditory processing.
The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP), 1998
Light is involved in providing entrainment of circadian rhythms and the suppression of the pineal... more Light is involved in providing entrainment of circadian rhythms and the suppression of the pineal hormone melatonin. In patients with affective disorders, there have been indications of circadian as well as seasonal variation in illness, which may be reflected in melatonin production. Varying sensitivity to light has been noted within healthy individuals as well as in some patients with affective disorders. Recent evidence suggests that patients with panic disorder may have an altered and phase-delayed melatonin rhythm. The present study examined the nocturnal plasma melatonin rhythm in patients with panic disorder, and also examined their melatonin sensitivity to dim light. The melatonin rhythm was examined in 6 patients with panic disorder and 8 controls. The melatonin sensitivity to dim white light (200 lx) was examined in 8 patients with panic disorder and 63 controls and was compared to that of a group of 7 patients with other anxiety disorders. Patients with panic disorder dem...
... Letter to the Editor. Cholinergic modulation of cognitive function in healthy subjects: acute... more ... Letter to the Editor. Cholinergic modulation of cognitive function in healthy subjects: acute effects of donepezil, a cholinesterase inhibitor. Pradeep J. Nathan PhD 1,* ,; Allison Baker 2 ,; Elaine Carr 2 ,; Jemima Earle 2 ,; Meaghan Jones 2 ,; Michelle Nieciecki 2 ,; Chris Hutchison 2 ...
The international journal of neuropsychopharmacology / official scientific journal of the Collegium Internationale Neuropsychopharmacologicum (CINP), 2012
In Alzheimer's disease (AD), progressive accumulation of β-amyloid (Aβ) peptides impairs nico... more In Alzheimer's disease (AD), progressive accumulation of β-amyloid (Aβ) peptides impairs nicotinic acetylcholine receptor (nAChR) function by a mechanism that may involve α7 and α4β2-nAChR subtypes. Additionally, the beta-site amyloid precursor protein (APP)-cleaving enzyme (BACE), the rate-limiting enzyme in the pathogenic Aβ production pathway, is expressed at high levels in hippocampal and cortical regions of AD brains. We measured hippocampal area CA1 protein levels of BACE and α7- and α4β2-nAChR subunits using an Aβ rat model of AD (14-d osmotic pump i.c.v. infusion of 300 pmol/d Aβ peptides) in the presence and absence of chronic stress and/or chronic nicotine treatment. There was a significant increase in the levels of BACE in Aβ-infused rats, which were markedly intensified by chronic (4-6 wk) stress, but were normalized in Aβ rats chronically treated with nicotine (1 mg/kg b.i.d.). The levels of the three subunits α7, α4 and β2 were significantly decreased in Aβ rats, b...
Estrogen may be involved in schizophrenia by inhibiting serotonin-1A (5-HT(1A)) receptor function... more Estrogen may be involved in schizophrenia by inhibiting serotonin-1A (5-HT(1A)) receptor function. We examined the effects of estrogen pre-treatment on modulation of loudness dependence of the auditory evoked potential (LDAEP) and mismatch negativity by the 5-HT(1A) receptor partial agonist, buspirone. Using a double-blind, placebo-controlled, repeated-measures design in healthy female volunteers, we observed that buspirone treatment significantly increased LDAEP slope. Estrogen increased LDAEP slope on its own, and a further LDAEP increase by buspirone was not seen after estrogen pre-treatment. Similar results were observed for mismatch negativity, where buspirone caused a small increase of latency, although not amplitude, after placebo but not estrogen pre-treatment, which enhanced mismatch negativity latency on its own. These results are in line with our previous findings on prepulse inhibition showing an inhibitory effect of estrogen on the action of buspirone. Taken together, these data suggest that estrogen may inhibit 5-HT(1A) receptor-mediated disruptions of auditory processing.
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Papers by Pradeep Nathan