cerebrospinal fluid amino acids

There are a large number of free amino acids in the nervous system. In addition to participating in the general metabolic process of the nervous system and maintaining the balance of intracellular and external water and electrolytes, these substances also act as chemical transfer substances involved in nerve excitation and inhibition, and are excited to nerve cells. Amino acids such as glutamic acid, aspartic acid and the like have an inhibitory action such as gamma aminobutyric acid (GABA) and glycine. Basic Information Specialist classification: neurological examination classification: cerebrospinal fluid examination Applicable gender: whether men and women apply fasting: fasting Tips: After lumbar puncture CSF, add 2ml of sodium sulfosalicylide sodium 5mg/ml to shake the precipitated protein, immediately put it into the curling, and put it into the -20 °C refrigerator within 10h or put it in -40 °C ~ -70 °C as soon as possible. . No more than 2 months. Blood contamination should be avoided (as the Asp content in red blood cells is 200 times higher than plasma). It is required to stop sampling after one week of taking the drug. Normal value HPLC method Aspartic acid (Aspartic Acid, Asp) 1.6 ± 1.7 μmol / L; Glutamic Acid (Glu) 4.6 ± 1.2 μmol / L; Serine (Serine, Ser) 33.9 ± 4.9 μmol / L; Histidine (Hisidine, His) 10.0 ± 2.7 μmol / L; Glycine (Gly) 8.6 ± 2.1 μmol / L; Threomine (Thr) 32.4 ± 12.6 μmol / L; Arginine (Arginine, Arg) 35.5 ± 6.1 μmol / L; Alanine (Alaine, Ala) 47.2 ± 9.1 μmol / L; Tyrosine (Tyr), 10.7±2.0 μmol/L; Cystine (Cystine, Cys) 1.0 ± 1.1 μmol / L; Methionine (Met) 0.3 ± 0.5 μmol / L; Proline (Vatine, Val) 18.7 ± 4.1 μmol / L; Phenylalanine (Phe) 12.0 ± 2.3 μmol / L; Isoleucine (Ileeucine, Ile) 6.5 ± 1.7 μmol / L; Leucine (Leu) 9.3 ± 2.7 μmol / L; Lysine (Lys), 22.2 ± 4.3 μmol / L. Clinical significance Under normal circumstances, the total amount of amino acids in CSF is about 10% to 30% of the plasma content. When the yellowing of various meningitis and spinal cord obstruction levels is yellow, the total amount of amino acids in CSF is significantly increased; the late stage neurosyphilis is slightly elevated; the multiple sclerosis and senile psychosis are decreased. More than 20 kinds of amino acids in CSF can be separated by chromatography. The clinical significance of amino acids is as follows. Bacterial meningitis, meningeal radiculitis, cancer meningitis, Garin-Bujadox-Bannnarth, etc. CSF glutamate, glycine, isoleucine, leucine, cystine, phenylalanine, proline high. Glycine and leucine are elevated in aseptic meninges CSF. Tuberculous meningitis, Japanese encephalitis, polio, CSF tryptophan increased. Brain abscess, systemic infection, schizophrenia, glycine, glutamate, proline, aspartate increased, schizophrenia also showed increased alanine. Hepatic coma, cerebral hemorrhage, epilepsy, severe narcolepsy, elevated glutamine, and decreased CSF gamma-aminobutyric acid concentration in patients with epilepsy. Many neurological degenerative diseases such as Parkinson's disease, motor neuron disease, spinal cerebellar degeneration, elevated aspartate in CSF, and decreased glutamate. The concentration of lysine and phenylalanine in cancer, glioblastoma CSF is increased. The amino acids in CSF of various amino acid urinary patients may change accordingly. For example, the content of branched chain amino acids such as guanidine, leucine and isoleucine in CSF of maple syrup is often increased, and the arginine content of arginine is increased. Increased, lysineuria CSF increased lysine. Low results may be diseases: high sclerosis results may be high disease: seizures and epilepsy syndrome, symptomatic epilepsy syndrome, meningitis, neurosyphilis precautions After lumbar puncture of CSF, add 2 ml of sodium sulfosalicylate 5 mg/ml to shake the precipitated protein, immediately put it into the curling pot, and then put it into the -20 °C refrigerator within 10 hours or put it in -40 ° C ~ -70 ° C as soon as possible. No more than 2 months. Blood contamination should be avoided (as the Asp content in red blood cells is 200 times higher than plasma). It is required to stop sampling after one week of taking the drug. More than 20 kinds of amino acids can be separated and determined by high performance liquid chromatography and amino acid analyzer. Some reported normal differences in the normal content, may be caused by the use of instruments, methods and specimen processing and storage conditions, and there are contradictions in the amino acid concentration changes in CSF of certain diseases, so the determination of amino acids in CSF Further research is needed for clinical significance. The amino acid content in CSF increased with age, including glutamic acid, serine, histidine, threonine, arginine, and cystine, but there was no gender difference. Inspection process (1) Desalting: 10 ml of the filtered cerebrospinal fluid was taken into a chromatography column containing 5 ml of Dowex-50×8 ion exchange resin, and the column was rinsed with 100 ml of distilled water, and the effluent was discarded. The amino acid was eluted with 30 ml of 2 mol/L aqueous ammonia. The eluate was evaporated in vacuo at 40 ° C and the residue was dissolved in 1 ml of distilled water. 1 ml of cerebrospinal fluid was firstly deproteinized by 40 mg of sulfosalicylic acid. After centrifugation, 0.5 ml of the supernatant was added to a chromatography column containing 1 ml of Dowex 50×8, and the column was rinsed with 40 ml of distilled water, and the effluent was discarded. The amino acid was eluted with 15 ml of 2 mol/L aqueous ammonia. The eluate was evaporated in vacuo at 40 ° C and the residue was dissolved in 0.05 ml distilled water. (2) Spotting: 4 μl of the demineralized concentrate of cerebrospinal fluid was added 1.5 cm from the left side of the thin layer chromatography plate; the amount of the sample was 2 μg of amino nitrogen, and the smaller the diameter, the better. (3) Oxidation of sulfur-containing amino acid: 0.5 μl of H2O2 containing ammonium molybdate was added to the spot and allowed to stand at room temperature for 30 minutes. (4) Spreading layer: Firstly, the thin layer chromatography plate is placed in a chromatography cylinder containing the first solvent, and the layer is stretched for about 60 minutes, that is, when the solvent is raised to 9.5 cm, it is taken out, and then blown in a 40 ° C air flow for 30 minutes. . The thin layer chromatography plate was rotated at 90 ° C and placed in a chromatography cylinder containing a second solvent for about 100 min, that is, when the solvent was raised to 9.5 cm, it was taken out and placed at 40 ° C overnight. (5) The ninhydrin reagent was sprayed onto the thin layer chromatography plate, and then placed in an oven at 100 ° C for 30 min to observe the purple-blue spots of the amino acid, and the proline spots were yellow. Not suitable for the crowd 1. If there is obvious papilledema or cerebral palsy, contraindications are contraindicated. 2. Patients who are in shock, exhaustion or endangered state and local skin inflammation, and lesions in the posterior cranial fossa are contraindicated. Adverse reactions and risks If the patient has symptoms such as breathing, pulse, or abnormal color during puncture, stop the operation immediately and deal with it accordingly.

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