Effects of Methylphenidate on Oxytocin and Vasopressin Levels in Pinealectomized Rats During Light–Dark Cycle

Appenrodt, E.; Bojanowska, Ewa; Janus, Jolanta; Stempniak, B; Guzek, Jan W.; Schwarzberg, H

doi:10.1016/s0091-3057(97)00242-6

Cited by 11 publications

(9 citation statements)

References 27 publications

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“…Rhythms persisted after pinealectomy and were significant for MSF and ENT, but not MUT, although a rhythm of MUT (as well as the other parameters) was seen in pinealectomised animals after osmotic stimulation. Such rhythms of firing activity are consistent with daily rhythms observed in the content of vasopressin in the pituitary (37) and plasma (4,6).…”

Section: Inter-spike Intervals Excitability and Neuropeptide Releasesupporting

confidence: 85%

“…This demonstrates a physiological relationship between the pineal gland and the neurohypophysial system. An increased MSF of phasic cells is consistent with the reduction in neurohypophysial vasopressin content after pinealectomy, especially in the morning (37) and in dehydrated animals (43). Reduced neurohypophysial hormone reserves may account for an attenuated response to osmotic stimulation after the pinealectomy (9).…”

Section: Discussionsupporting

confidence: 68%

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Daily Rhythms of Spike Coding in the Rat Supraoptic Nucleus

Bhumbra

Lombardelli

Gonzalez

et al. 2009

J Neuroendocrinology

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Novel measures of coding based on interspike intervals were used to characterise the rhythms of single unit activity in the supraoptic nucleus during the day/night cycle in urethane-anaesthetised rats in vivo. Both continuously firing and phasic cells showed significant (P < 0.001) diurnal rhythms of spike frequency and in the irregularity of firing, as quantified by the log interval entropy (ENT). Comparison of rhythms in log interval ENT showed that the amplitude of the rhythms was greater for the continuously firing cells than for the phasic cells (P = 0.002). Rhythms persisted after hypertonic stimulation or pinealectomy and both treatments reduced the amplitude significantly only for the continuously firing cell group. By contrast, the mesor (i.e. mid-point of the rhythm) was reduced only for the phasic cell group. A similar analysis applied to the activity of cells of the suprachiasmatic nucleus showed that, after pinealectomy, there was a significant rhythm in ENT (P < 0.001) but not firing rate; however, the amplitude of the rhythm in ENT was attenuated (P = 0.047). Diurnal changes in the electrical activity of supraoptic cells are consistent with previously reported circadian changes in magnocellular neuropeptide release. Differences between continuous and phasic cell groups in the effects of osmotic stimulation on rhythmic activity indicate that the two cell types differ in their coding of osmolality and zeitgeber time information. The different effects of pinealectomy on the supraoptic and suprachiasmatic nuclei suggest that removal of endogenous melatonin unmasks a difference in circadian coding between the two nuclei.

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Section: Inter-spike Intervals Excitability and Neuropeptide Releasesupporting

confidence: 85%

Section: Discussionsupporting

confidence: 68%

Daily Rhythms of Spike Coding in the Rat Supraoptic Nucleus

Bhumbra

Lombardelli

Gonzalez

et al. 2009

J Neuroendocrinology

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“…Six of the seven studies (Gaytan et al, 1996(Gaytan et al, , 1997b(Gaytan et al, , 2000Honma & Honma, 1992; focused on the locomotor effects of MPD while only one (Appenrodt et al, 1997) examined the effect of MPD on the circadian rhythm of endogenous substances (oxytocin and vasopressin).…”

Section: Effect Of Acute Mpd Administration On Locomotionmentioning

confidence: 99%

“…Several studies investigated the effects of specific brain lesions in relation to hormonal levels (Appenrodt et al, 1997) and locomotor activity (Honma & Honma, 1992;. Pinealectomy influenced both the daily pattern and levels of oxytocin and vasopressin.…”

Section: Effect Of Brain Lesions On Mpd Effectsmentioning

confidence: 99%

“…Pinealectomy influenced both the daily pattern and levels of oxytocin and vasopressin. Subsequent MPD administration further influenced oxytocin and vasopressin levels in plasma, the hypothalamus, and the neurohypophysis in complex ways (Appenrodt et al, 1997). Lesion of either the Substantia Nigra or the Red Nucleus resulted in an increase in total activity in both light and dark conditions, but the normal light-dark cycle of elevated activity in the dark compared to the light was preserved .…”

Section: Effect Of Brain Lesions On Mpd Effectsmentioning

confidence: 99%

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Methylphenidate (Ritalin): Behavioral Studies in the Rat

Askenasy

Taber

Peng

et al. 2007

International Journal of Neuroscience

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Attention Deficit Hyperactivity Disorder (ADHD) is a neuropsychiatric syndrome with an onset in childhood characterized by an inability to remain focused or to concentrate for prolonged periods of time. Children suffering from this disease are many times described as either inattentive or as hyperactive-impulsive depending on what form of the disease they manifest. Methylphenidate is the preferred treatment for this behavioral disorder and is used for long term disease management. Much still remains unknown concerning this stimulant and its effects on behavior and future abuse potential are pertinent questions. Since animal models are used to study the mechanism of drug action and rats are used often in drug studies, the objective of this review is to summarize the research reports that mainly have used rats as the model to investigate the action of methylphenidate. Topics discussed in this review include: (1) What effect does a single dose of methylphenidate have on locomotion activity; (2) Does repeated administration of methylphenidate result in tolerance or sensitization; and (3) Does methylphenidate have rewarding properties as measured by the self-administration and condition placed preference paradigms.

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Motility and Passive Avoidance Modulation by Septal Vasopressin is Dependent on the Pineal Gland

Schwarzberg

Appenrodt

2002

Advances in Experimental Medicine and Biology

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Effects of Methylphenidate on Oxytocin and Vasopressin Levels in Pinealectomized Rats During Light–Dark Cycle

Cited by 11 publications

References 27 publications

Daily Rhythms of Spike Coding in the Rat Supraoptic Nucleus

Daily Rhythms of Spike Coding in the Rat Supraoptic Nucleus

Methylphenidate (Ritalin): Behavioral Studies in the Rat

Motility and Passive Avoidance Modulation by Septal Vasopressin is Dependent on the Pineal Gland

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