Increased tyrosine availability increases brain regional DOPA levels in vivo

Brodnik, Zachary D.; Bongiovanni, Rodolfo; Double, Manda; Jaskiw, George E.

doi:10.1016/j.neuint.2012.07.012

Cited by 16 publications

(25 citation statements)

References 51 publications

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“…To put these numbers in perspective, the World Health Organization's daily upper requirement of TYR is 14 mg/kg (see Deijen, 2005), meaning an individual weighing 70 kg needs to consume approximately 1 g of TYR per day for normal functioning. Doses far exceeding 1 g are unlikely to confer any additional benefits, as the rate-limiting TH enzyme is assumed to be close to saturation under normal circumstances (Brodnik et al, 2012). Consistent with this idea, TYR transport across cell membranes decreases in healthy individuals after TYR supplementation (Wiesel et al, 1999).…”

Section: Authorsmentioning

confidence: 92%

“…However there are a number of reasons why TYR supplementation might be preferable. First of all, the TH enzyme already being near saturation under normal circumstances (Brodnik et al, 2012) can be considered a positive characteristic, as it prevents large amounts of TYR being converted. In contrast, the conversion of L-DOPA into DA does not depend on such a ratelimiting factor, allowing far larger increases in catecholamines but also significantly increasing the risk of inducing levels that are detrimental for performance (Goldman-Rakic et al, 2000;Muly et al, 1998).…”

Section: Authorsmentioning

confidence: 99%

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Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands—A review

Jongkees

Hommel

Kühn

2015

Journal of Psychiatric Research

120

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Section: Authorsmentioning

confidence: 92%

Section: Authorsmentioning

confidence: 99%

Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands—A review

Jongkees

Hommel

Kühn

2015

Journal of Psychiatric Research

120

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“…Probes were flushed with Dulbecco’s phosphate buffered saline (in milliequivalents: 137 NaCl, 2.7 KCl, 0.5 MgCl2, 1.5 KH2PO4, 8.1 Na2HPO4, 1.2 CaCl2, and 5 % glucose at pH 7.4) overnight at 0.2 μl/min. Microdialysis experiments began on the following morning, and were completed as previously described (Brodnik et al, 2012; Brodnik et al, 2017a). …”

Section: 0 Methodsmentioning

confidence: 99%

Susceptibility to traumatic stress sensitizes the dopaminergic response to cocaine and increases motivation for cocaine

et al. 2017

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Patients with post-traumatic stress disorder have a heightened vulnerability to developing substance use disorders; however, the biological underpinnings of this vulnerability remain unresolved. We used the predator odor stress model of post-traumatic stress disorder with segregation of subjects as susceptible or resilient based on elevated plus maze behavior and context avoidance. We then determined behavioral and neurochemical differences across susceptible, resilient, and control populations using a panel of behavioral and neurochemical assays. Susceptible subjects showed a significant increase in the motoric and dopaminergic effects of cocaine, and this corresponded with heightened motivation to self-administer cocaine. Resilient subjects did not show differences in the motoric effects of cocaine, in dopamine signaling vivo, or in any measure of cocaine self-administration. Nonetheless, we found that these animals displayed elevations in both the dopamine release-promoting effects of cocaine and dopamine autoreceptor sensitivity ex vivo. Our results suggest that the experience of traumatic stress may produce alterations in dopamine systems that drive elevations in cocaine self-administration behavior in susceptible subjects, but may also produce both active and passive forms of resilience that function to prevent gross changes in cocaine’s reinforcing efficacy in resilient subjects.

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“…Other mechanisms involve in increasing brain NE are either inhibition of enzymes monoamine oxidase or catechol-o-methyl transferase (Huotari et al, 2002). The production of NE in brain also varies notably by means of its precursor L-tyrosine and significantly increases by tyrosine modulation (Brodnik et al, 2012). Free tyrosine levels are controlled by tissue flux through fat metabolism while its entry in the brain increases after competition with other amino acids for a common transport system (Fernstrom, 1990).…”

Section: Discussionmentioning

confidence: 99%

Brown seaweeds administration generate psychotherapeutic response associated with brain norepinephrine modulation in rats

Khan¹,

Uddin²,

Khaliq³

et al. 2017

J. Pharmacognosy Phytother.

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Research in the area of herbal psychopharmacology has increased considerably over the past few decades in search of panacea for neuroprotection. Seaweeds are one of the herbal sources consumed in many Asian countries as medicine due to their remarkable bioprospecting properties and evident health benefits. Keeping in view the bioactive potential of seaweeds, the present study was designed to evaluate the psychotherapeutic potential of Sargassum swartzii and Stoechospermum marginatum, in association with the role of brain norepinephrine (NE) using a rat model. Adult male albino Wistar rats were divided into three groups (n=6) as control rats (CR), S. swartzii extract treated (SSET) and S. marginatum extract treated (SMET). Seaweeds were extracted using methanol and administered orally to rats for four weeks at a dose of 60 mg/kg. Behavioral changes for stimulant activities were assessed by activity cage and open field tests, while anxiety was observed in light-dark exploration test. Followed by scoring behavioral activities, rats were decapitated and brain samples taken out from the cranial cavity were immediately stored at -70°C until estimation of brain NE levels by high performance liquid chromatography-electrochemical detection (HPLC-ECD). Results exhibited an increase in ambulatory and anxiolytic activities by SSET and SMET rats with subsequent increase in brain NE as compared to CR. The increase in NE in SSET and SMET rats could be attributed to the lipolytic activity of seaweeds. However, the exact mechanism underlying the increase in NE needs further investigations. In conclusion, seaweed extracts showed significant psychostimulant and anxiolytic activity by ameliorating brain NE levels and could be studied further for isolation of active ingredients responsible for eliciting such a response.

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Increased tyrosine availability increases brain regional DOPA levels in vivo

Cited by 16 publications

References 51 publications

Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands—A review

Effect of tyrosine supplementation on clinical and healthy populations under stress or cognitive demands—A review

Susceptibility to traumatic stress sensitizes the dopaminergic response to cocaine and increases motivation for cocaine

Brown seaweeds administration generate psychotherapeutic response associated with brain norepinephrine modulation in rats

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