2002 — 2006 |
Zhdanova, Irina V. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Melatonin and Aging in Non-Human Primates @ Boston University Medical Campus
DESCRIPTION (provided by applicant): The goals of the proposed project are to determine the age-related changes in sleep, temperature regulation, hormonal secretion and morphological integrity of the suprachiasmatic nuclei (SCN) of the hypothalamus in non-human primates and the contribution of melatonin to the maintenance of consolidated nocturnal sleep, thermoregulation and cognitive performance in aged monkeys. Using a lesion-replacement approach, we will also determine the extent to which sleep-promoting and hypothermic effects of melatonin depend on the integrity of the SCN. This will be accomplished by comparing sleep quantity and quality, cognitive performance, the amplitude and temporal patterns of the circadian body rhythms (temperature, hormonal secretion), as well as the effects of melatonin treatment, in old primates to young control animals and young monkeys that receive lesions of the pineal gland (Px), SCN (SCNx) or both pineal and SCN (Px/SCNx). Subjects will be young (5.9 yrs of age) and old (20-24 yrs of age) rhesus monkeys. Five experimental groups (9 monkeys in each group, 45 total) will be tested, including: (1) aged 'operated-on' animals; (2) young adults with Px; (3) young adults with SCNx; (4) young adults with combined Px/SCNx lesions; and (5) young adult 'operated-on' control monkeys. Sleep (polysomnography) and core body temperature will be measured using implanted telemetric probes, activity rhythms will be recorded actigraphically, plasma melatonin and cortisol levels will be measured using radioimmunoassay and cognitive performance will be assessed using neuropsychological tasks. The morphological integrity of the SCN and quality of surgical lesions will be documented using pre- and post-surgery MRI and post-mortem morphological analysis of brain tissue. Comparing different groups of monkeys (old vs. young; old or young vs. Px, SCNx or PxISCNx; Px or SCNx vs. Px/SCNx) and also using within-subject design (comparing measures collected at baseline and after the brain surgery), while documenting morphological integrity of SCN and pineal in each animal, will allow us to determine the contribution of age-related changes in the pineal or SCN to the maintenance of sleep, cognitive functions and circadian body rhythms of temperature and hormonal secretion. This approach will also allow determining the role of melatonin in primate sleep and whether the acute sleep-promoting and hypothermic effects of melatonin are mediated via the SCN.
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0.914 |
2003 — 2005 |
Zhdanova, Irina V. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Cocaine-Induced Behaviors in Larval Zebrafish @ Boston University Medical Campus
DESCRIPTION (provided by applicant): The goal of the proposed studies is to establish the behavioral correlates of cocaine administration and cocaine withdrawal in zebrafish. The central hypothesis of this proposal is that neurobiological mechanisms of drug reward and drug addiction in lower vertebrates are similar to those in mammals and that investigating them in zebrafish, a lower diurnal vertebrate with well-characterized genetics, would lead to a better understanding of addictive disorders and the development of more effective treatment strategies. This requires a detailed characterization of species-specific responses to cocaine in zebrafish and the evaluation of methodological approaches applicable to large-scale screening procedures. The proposed studies will be accomplished by conducting: i) automatic recordings of zebrafish locomotor activity and conditioned place preference, using digital image analysis system; and ii) high-speed digital imaging of swimming and turning patterns in larval zebrafish. These techniques will allow us to: a) Characterize the effects of cocaine treatment and cocaine withdrawal on locomotor activity and its circadian pattern in larval zebrafish; b) Establish whether zebrafish larvae develops behavioral sensitization to cocaine; c) Determine whether zebrafish larvae develops place preference to cocaine; d) Characterize the effects of cocaine treatment and cocaine withdrawal on specific locomotor patterns, e.g., swimming and turning; e) Determine whether melatonin treatment can modulate cocaine-induced changes in zebrafish behavior. A detailed characterization of the behavioral responses to cocaine in larval zebrafish would create a necessary foundation for intensive studies on the molecular and neuronal mechanisms of drug addiction, using multiple mutant phenotypes and transgenic zebrafish available. This could advance our understanding of the neuronal and intracellular targets of addictive substances and the genetic bases of vulnerability to drug addiction.
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0.914 |
2003 — 2004 |
Zhdanova, Irina V. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Melatonin, Behavior and Neuronal Activity in Zebrafish @ Boston University Medical Campus
DESCRIPTION (provided by applicant): The long-term goal of our studies is to identify the mechanisms mediating the physiological effects of melatonin on human sleep and circadian rhythms, and to apply this knowledge to designing new therapeutic strategies for insomnia. Our recent studies have established that rest state in diurnal genetically well-characterized lower vertebrate, zebrafish, has critical behavioral similarities with sleep and that melatonin can promote a sleep-like state in zebrafish via specific melatonin receptors. The goals of the proposed project are to determine the contribution of overnight melatonin receptor activation by endogenous melatonin to quantitative parameters of nighttime sleep-like state and the circadian rhythm of activity in zebrafish, to identify melatonin receptor subtypes responsible for sleep and circadian modulation, and to identify the reticulospinal neurons mediating locomotor effects of melatonin treatment. The effects of melatonin on sleep-like state and circadian rhythm parameters will be assessed in wild-type and melatonin receptor knockdown larval zebrafish using: i) high throughput automatic image analysis system for locomotor activity recordings; ii) melatonin receptor ligands with different affinity to melatonin receptor subtypes and inhibition of melatonin synthesis; iii) knockdown of melatonin receptor subtypes with antisense morpholino oligonucleotides; iv) in vivo confocal calcium imaging for monitoring spontaneous and evoked activity of individual neurons during high-speed recordings of larval locomotor behavior; v) laser ablation of candidate neurons under confocal microscope, followed by behavioral evaluation. These studies would clarify the role of endogenous melatonin in sleep regulation in the diurnal vertebrate, characterize functional specificity of melatonin receptors and role of reticulospinal neurons in locomotor effects of melatonin. They would also constitute a background for the identification of neuronal networks and intracellular signaling pathways mediating the effects of melatonin on sleep-like state and circadian rhythmicity. Furthermore, a continuation of these studies on the physiological regulation of the sleep-like state in zebrafish, in conjunction with the availability of multiple zebrafish mutants and a complete sequence of zebrafish genome soon to be available, could potentially lead to a better understanding of the genetic basis of sleep regulation and sleep function in vertebrates.
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0.914 |
2005 — 2006 |
Zhdanova, Irina V. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Melatonin, Behavior and Neuronal Activity @ Boston University Medical Campus
DESCRIPTION (provided by applicant): The long-term goal of our studies is to identify the mechanisms mediating the physiological effects of melatonin on human sleep and circadian rhythms, and to apply this knowledge to designing new therapeutic strategies for insomnia. Our recent studies have established that rest state in diurnal genetically well-characterized lower vertebrate, zebrafish, has critical behavioral similarities with sleep and that melatonin can promote a sleep-like state in zebrafish via specific melatonin receptors. The goals of the proposed project are to determine the contribution of overnight melatonin receptor activation by endogenous melatonin to quantitative parameters of nighttime sleep-like state and the circadian rhythm of activity in zebrafish, to identify melatonin receptor subtypes responsible for sleep and circadian modulation, and to identify the reticulospinal neurons mediating locomotor effects of melatonin treatment. The effects of melatonin on sleep-like state and circadian rhythm parameters will be assessed in wild-type and melatonin receptor knockdown larval zebrafish using: i) high throughput automatic image analysis system for locomotor activity recordings; ii) melatonin receptor ligands with different affinity to melatonin receptor subtypes and inhibition of melatonin synthesis; iii) knockdown of melatonin receptor subtypes with antisense morpholino oligonucleotides; iv) in vivo confocal calcium imaging for monitoring spontaneous and evoked activity of individual neurons during high-speed recordings of larval locomotor behavior; v) laser ablation of candidate neurons under confocal microscope, followed by behavioral evaluation. These studies would clarify the role of endogenous melatonin in sleep regulation in the diurnal vertebrate, characterize functional specificity of melatonin receptors and role of reticulospinal neurons in locomotor effects of melatonin. They would also constitute a background for the identification of neuronal networks and intracellular signaling pathways mediating the effects of melatonin on sleep-like state and circadian rhythmicity. Furthermore, a continuation of these studies on the physiological regulation of the sleep-like state in zebrafish, in conjunction with the availability of multiple zebrafish mutants and a complete sequence of zebrafish genome soon to be available, could potentially lead to a better understanding of the genetic basis of sleep regulation and sleep function in vertebrates.
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0.914 |
2009 — 2013 |
Zhdanova, Irina V. |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Circadian System and Prenatal Cocaine in Zebrafish @ Boston University Medical Campus
DESCRIPTION (provided by applicant): The goal of the proposed project is to establish the role of the circadian system in the prenatal effects of cocaine exposure during a critical period of embryonic brain development in a diurnal vertebrate, zebrafish. These studies will be based on the results of the previous 3-year funding period, which established a reciprocal relationship between the cocaine and zebrafish clock system, found that melatonin can counteract the effects of cocaine on brain development, identified two strains with contrasting effects of cocaine on circadian system and behavioral effects of cocaine, and characterized the behavioral and molecular effects of cocaine and cocaine withdrawal in adult and aged zebrafish of both genders. The continuation of this research will specifically focus on characterization of the effects of cocaine and circadian clock system on brain development, and address the hypothesis that reciprocal interaction between the two is due to their contrasting effects on neuronal proliferation during early stages of brain formation. The Specific Aims will address: 1) In-depth characterization of the effects of early cocaine and melatonin exposure on zebrafish brain development and gene expression; 2) An impact of the earlier identified genetic variation in circadian response to cocaine on the effects of prenatal cocaine and melatonin exposure; 3) The role of circadian deficits in the prenatal brain development and effects of cocaine, and whether exogenous melatonin can counteract these effects. Zebrafish will be exposed to cocaine during the major periods of cortical (pallium) and limbic system (dorsomedial and dorsolateral telencephalon) development, synchronized with either the nighttime or daytime circadian phase. Melatonin will be administered prior to cocaine at different circadian phases, in embryos with normal and deficient circadian system. The brain size, cell division rate, dopamine levels, expression of the circadian genes and those encoding for the melatonin receptors, dopamine transporter, cyclin-dependent kinases, cyclin A and growth hormone will be evaluated throughout development and maturation. The time of development and integrity of the neuronal ensembles will be evaluated in transgenic fish with fluorescent markers for alpha-1-tubulin and f-spondin. The cocaine-induced changes in the locomotor activity and sleep will be documented during early post-natal period. Understanding the role of the circadian factors in brain development and mechanisms through which they attenuate prenatal effects of cocaine, should help to design preventive and therapeutic strategies to counteract prenatal cocaine impact on early brain development or subsequent changes in brain functions.
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0.914 |