Related Experiment Video
Updated: Jul 17, 2026
05:51
Induction and Assessment of Levodopa-induced Dyskinesias in a Rat Model of Parkinson's Disease
Published on: October 14, 2021
Nitrous oxide promotes hyperhomocysteinemia in levodopa treated rats
Nils Henninger1, Qi Wang, Jürgen G Okun
1Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01655, USA. Nils.Henninger@umassmed.edu
Parkinsonism & Related Disorders
|January 24, 2007
Summary
Nitrous oxide (N2O) exposure worsens levodopa-induced hyperhomocysteinemia in rats. Entacapone co-treatment prevented this increase, while folate did not significantly alter total homocysteine (tHcy) levels.
Area of Science:
- Pharmacology
- Neuroscience
- Biochemistry
Background:
- Levodopa is a primary treatment for Parkinson's disease.
- Nitrous oxide (N2O) exposure is known to affect homocysteine metabolism.
- Hyperhomocysteinemia is a potential risk factor for various health issues.
Purpose of the Study:
- To investigate if N2O exposure exacerbates levodopa-induced hyperhomocysteinemia.
- To determine if folate or entacapone co-administration can mitigate elevated total plasma homocysteine (tHcy) levels.
Main Methods:
- Male Wistar rats were used in a controlled experimental setting.
- Animals were randomly assigned to five groups: vehicle/N2O, levodopa/nitrogen, levodopa/N2O, levodopa/N2O+folate, and levodopa/N2O+entacapone.
- Total plasma homocysteine (tHcy) levels were measured at multiple time points post-anesthesia.
Main Results:
- The combination of N2O exposure and levodopa treatment significantly increased tHcy levels in rats.
- Co-administration of entacapone effectively prevented the N2O-exacerbated hyperhomocysteinemia.
- Folate co-administration did not show a significant preventative effect on tHcy levels.
Conclusions:
- N2O exposure potentiates levodopa-induced hyperhomocysteinemia in a rat model.
- Entacapone demonstrates a protective effect against this adverse metabolic change.
- Folate is not effective in preventing N2O-exacerbated hyperhomocysteinemia when co-administered with levodopa.
Related Concept Videos
01:24Parkinson's Disease: Treatment
Neurodegenerative disorders, such as Parkinson's Disease (PD), involve the gradual and irreversible destruction of neurons in particular brain areas. These disorders exhibit standard features like proteinopathies, selective vulnerability of some neurons, and an interaction of intrinsic properties, genetics, and environmental influences in neural injury.
Parkinson's Disease is primarily a result of the loss of dopaminergic neurons in the substantia nigra pars compacta. The cornerstone of its...
Parkinson's Disease is primarily a result of the loss of dopaminergic neurons in the substantia nigra pars compacta. The cornerstone of its...
01:29Drugs Affecting Neurotransmitter Synthesis
Drugs affecting neurotransmitter synthesis can impact the adrenergic neuron and the synthesis of neurotransmitters. For example, α-methyltyrosine and carbidopa target specific enzymes involved in catecholamine synthesis. α-methyltyrosine inhibits the enzyme tyrosine hydroxylase, which converts tyrosine into dopamine. By blocking this enzyme, α-methyltyrosine reduces dopamine production and other catecholamines. Carbidopa, on the other hand, inhibits the enzyme dopa decarboxylase, which converts...
01:28Drugs Affecting GI Tract Motility: Dopamine Receptor Antagonists
Prokinetic agents are specialized medications that stimulate gastrointestinal (GI) motility, promoting food movement through the GI tract. Dopamine, an inhibitory neurotransmitter, plays a significant role in this process, reducing GI motility and indirectly controlling the speed of digestion. Dopamine receptor antagonists, such as metoclopramide and domperidone, offer a unique advantage as prokinetic agents. By blocking the dopamine receptors, these drugs increase GI motility, improving food...
01:202° Amines to N-Nitrosamines: Reaction with NaNO2
Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.
01:29Chemotherapy-Induced Nausea and Vomiting: Dopamine Receptor Antagonists
Dopamine receptor antagonists, also known as antipsychotic agents, are critical in managing chemotherapy-induced vomiting. These antiemetic agents block dopamine receptors in the chemoreceptor trigger zone (CTZ), inhibiting signal transmission to the vomiting center. Antipsychotic agents encompass phenothiazines (PTZ), butyrophenones, benzamides, and thienobenzodiazepines (Zyprexa), which are utilized for their antiemetic and sedative properties.
Phenothiazines, such as prochlorperazine...
Phenothiazines, such as prochlorperazine...
01:24Drug Toxicity: Risk factors
Adverse Drug Reactions (ADRs) are potential complications that arise during pharmacotherapy, influenced by multiple risk factors. Age plays a significant role; both neonates and the elderly are at heightened risk due to their respective immature and diminished metabolic and elimination processes. Gender also impacts ADRs, with females experiencing a 1.5 to 1.7-fold greater risk than males, which may be linked to pharmacokinetic, pharmacodynamic, and hormonal differences. Notably, neonates, the...