Distribution of 3,4-dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylglycol (DOPEG) in microdissected brain structures and the pituitary gland: Metabolite changes in the median eminence in response to hyperprolactinemia and suckling

Mechanick, Jeffrey I.; Cohen-Becker, Ilene R.; Gregerson, Karen A.; Selmanoff, Michael

doi:10.1007/bf02098498

Cited by 13 publications

(6 citation statements)

References 53 publications

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“…In particular, there was a specificlinear fall for DOPAC and DOPAC/DA values and a speci fic linear increase for 5-HIAA/5-HT values between 10.00 and 17.00 h on proestrus. In addition, the DOPAC/DA ratio was changing in the opposite direction on proestrus versus estrus.The values we reported for DA [15,34, 39, 46] and DOPAC [18,34] are within the range of earlier reports. There was some similarity in the DOPAC/DA and 5-HIAA/5-HT ratio patterns on DI, DII and estrus when both were high.…”

supporting

confidence: 77%

Median Eminence Dopamine and Serotonin Neuronal Activity

Kerdelhué¹,

Bojda²,

Lesieur

et al. 1989

Neuroendocrinology

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Using a high-performance liquid chromatography (HPLC) system coupled with an electrochemical detector, the concentrations of dopamine (DA) and 5-hydroxytryptamine (5-HT) and their major specific metabolites 3,4-dihydroxy-phenylacetic acid (DOPAC) and 5-hydroxyindole-3-acetic acid (5-HIAA), respectively, were measured in the median eminence (ME) throughout the rat estrous cycle. The ME DA content remained fairly constant throughout the estrous cycle except on estrus when Π.OOh values were significantly lower than 10.00 h values (40% decrease, p < 0.05). The ME 5-HT content determined at 10.00 h was higher on proestrus than on any other day of the cycle. The ME DOPAC concentrations did not differ between 10.00 and 17.00 h on diestrus I, diestrus II or estrus. On the contrary, there was an almost linear decline between 10.00 and 17.00 h on proestrus (36% decrease, p < 0.05). The ME 5-HIAA content did not differ between 10.00 and 17.00 h on any day of the estrous cycle. Significant changes were recorded for the DOPAC/DA and 5-HIAA/ 5-HT ratio in the ME on proestrus. There was a progressive decrease, starting from 10.00 in the DOPAC/DA ratio with minimal values (42% decrease, p < 0.05) at 16.00 h followed by an increase from 16.00 to 19.00 h. On the other hand, the 5-HIAA/5-HT ratio increased between 10.00 and 17.00 h (97% increase, p < 0.05) and subsequently declined until 19.00 h (67% decrease vs. 17.00 h, p < 0.05). These data show that a concomitant decrease in dopaminergic activity and increase in serotoninergic activity in the ME occur in association with the preovulatory prolactin and luteinizing hormone preovulatory surges.

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supporting

confidence: 77%

Median Eminence Dopamine and Serotonin Neuronal Activity

Kerdelhué¹,

Bojda²,

Lesieur

et al. 1989

Neuroendocrinology

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“…6). Similar increases in pituitary DA in response to PRL have been reported in male rats [27], The E2-induced increase in pituitary DA is not mediated, but can be enhan ced by prolactinemia. We speculate that E2 and PRL act at different loci to increase pituitary DA.…”

Section: Discussionsupporting

confidence: 56%

Hormonal Influences on the Estradiol-Induced and Age-Related Increases of Pituitary Dopamine in C57BL/6J Mice

Telford

Sinha²,

Finch³

1987

Neuroendocrinology

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Estradiol (E₂) produces many-fold increases in the dopamine (DA) content of the anterior pituitary and also plays a role in the age-related increase in pituitary DA in female C57BL/6J mice. These studies address the following questions: (1) What are the time and dose characteristics of the E₂-induced increase in pituitary DA and can other gonadal steroids – such as progesterone (P) and 5α-dihydrotestosterone – also influence pituitary DA? (2) Is the age-related increase in pituitary DA due entirely to an increase in the E₂:P ratio seen in aging female mice, or can extra-ovarian factors also play a role? (3) Is the E2-induced (and therefore possibly the age-related) increase in pituitary DA secondary to an E₂-induced increase in serum prolactin? In ovariectomized (OVX) mice, E2 implants increased pituitary DA in a time- and dose-dependent fashion. P implants administered to OVX mice simultaneously with E₂ antagonized the E₂-induced increase in pituitary DA. Daily injections of 5α-dihydrotestosterone given in conjunction with E₂ implants had no effect on basal or E₂-increased pituitary DA in OVX mice. Thus, E₂ is the only gonadal steroid examined which increases anterior pituitary DA. In intact aging mice, P attenuates the age-related increase in pituitary DA, supporting the hypothesis that the increased ratio of E₂:P secreted by the ovaries of aging female mice is responsible for the age-related increase in pituitary DA. However, at advanced ages, intact male mice also showed modest increases in anterior pituitary DA. Therefore, extra-ovarian age changes, perhaps age changes intrinsic to the pituitary, also play a minor role in the age-related increase in pituitary DA. E₂ increases the secretion of prolactin, which can then feed back to increase secretion of DA from the tuberoinfundibular dopaminergic neurons, a source of pituitary DA. To determine if the E₂-induced increase in pituitary DA was secondary to an E₂-induced increase in serum prolactin, OVX mice were given pituitary grafts to increase serum prolactin independently of E₂ treatment. The E₂-induced increase of pituitary DA is not mediated, but can be enhanced by prolactinemia.

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“…Terminal degeneration can occur via oxidative stress, which can be produced by DA-derived reactive oxygen species and quinones (Cohen, 1987). Consequently, the cortex may be less vulnerable to the detrimental effects of DA-associated free radicals because it contains lower concentrations of DA than the striatum (Mechanick et al, 1987, current study). In fact, methamphetamine produces relatively less of an increase in extracellular DA (Kashihara et al, 1991), a reduced level of oxidative stress (Gluck et al, 2001), as well as minimal DAergic damage (Ricaurte et al, 1980;Stephans et al, 1998) in the frontal cortex compared to the striatum, suggesting that DA neurons in the frontal cortex may be relatively resistant to the effects of DA-derived oxidative stress.…”

Section: Discussionmentioning

confidence: 91%

Chronic unpredictable stress augments +3,4-methylenedioxymethamphetamine-induced monoamine depletions: The role of corticosterone

Johnson

Yamamoto

2009

Neuroscience

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Exposure to stress alters the behavioral and neurochemical effects of drugs of abuse. However, it is unknown if chronic stress can affect the serotonergic depletions induced by the psychostimulant drug 3,4-methylenedioxymethamphetamine (MDMA). Rats were exposed to 10 days of chronic unpredictable stress (CUS) which resulted in the predicted elevation of basal plasma corticosterone concentrations. On the 11th day, rats received 4 challenge doses of MDMA (5 mg/kg every 2 h, i.p.) or saline. Five days later, rats were killed and 5-HT and dopamine content were measured in the striatum, hippocampus, and frontal cortex. MDMA produced greater depletions of 5-HT in all 3 brain regions of rats pre-exposed to CUS compared to rats not exposed to CUS. CUS-exposed rats also had an augmented acute hyperthermic response but a similar increase in plasma corticosterone after challenge injections of MDMA compared with non-stressed rats similarly challenged with MDMA. Moreover, CUS-exposed rats exhibited an MDMA-induced depletion of striatal dopamine that was absent in non-stressed rats that received MDMA. To investigate the role of corticosterone in these effects, the corticosterone synthesis inhibitor, metyrapone (50 mg/kg, i.p.), was administered prior to each stressor on each of the 10 days of CUS. Metyrapone blocked the chronic stress-induced elevation in basal plasma corticosterone, prevented the enhancement of MDMA-induced hyperthermia, and blocked the enhanced depletions of 5-HT and dopamine in CUS-exposed rats, but had no effect on the acute MDMA-induced increases in plasma corticosterone. These findings suggest that CUS alone can increase the basal level of corticosterone that in turn, plays an important role in enhancing the sensitivity of both 5-HT and dopamine terminals to the hyperthermic and monoamine depleting effects of MDMA without altering the acute corticosterone response to an MDMA challenge.

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Distribution of 3,4-dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylglycol (DOPEG) in microdissected brain structures and the pituitary gland: Metabolite changes in the median eminence in response to hyperprolactinemia and suckling

Cited by 13 publications

References 53 publications

Median Eminence Dopamine and Serotonin Neuronal Activity

Median Eminence Dopamine and Serotonin Neuronal Activity

Hormonal Influences on the Estradiol-Induced and Age-Related Increases of Pituitary Dopamine in C57BL/6J Mice

Chronic unpredictable stress augments +3,4-methylenedioxymethamphetamine-induced monoamine depletions: The role of corticosterone

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