Preparation of Artificial CSF
Artificial cerebrospinal fluid (CSF) more closely mirrors the composition of endogenous CSF, and is therefore more physiologically compatible. Following is a method for preparing artificial CSF.
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1. Preparation of Solution A
Dissolve in 500 ml pyrogen-free, sterile water:
| Compound | (g) |
|---|---|
| NaCl | 8.66 |
| KCl | 0.224 |
| CaCl2 · 2H2O | 0.206 |
| MgCl2 · 6H2O | 0.163 |
2. Preparation of Solution B
Dissolve in 500 ml pyrogen-free, sterile water:
| Compound | (g) |
|---|---|
| Na2HPO4 · 7H2O | 0.214 |
| NaH2PO4 · H2O | 0.027 |
3. Preparation of Artificial CSF
Combine solutions A and B in a 1:1 ratio.
4. Composition of Cerebrospinal Fluid in Various Species 1
| Ion/Compound | Human | Dog | Cat | Rabbit |
|---|---|---|---|---|
| Na | 187.5 | 153.5 | 160 | 149* |
| K | 2.6 | 3.1 | 4.4 | 2.9* |
| Ca | 1.1 | 1.4 | 1.4 | 1.24* |
(Concentration in mM)
*Note : Only one reference listed a concentration level. Therefore, the listed value was used.
1 Ion concentrations (except for the levels indicated with an asterisk) are an average of the data listed in Davson, H. Physiology of the Cerebrospinal Fluid, J. & A. Churchill, Ltd., London, 1967 and Biology Data Book , Volume III, 2nd ed., Fed. Am. Soc. Exper. Biol., Washington D.C., 1974
| Ion/Compound | Human | Dog | Cat | Rabbit |
|---|---|---|---|---|
| Na | 187.5 | 153.5 | 160 | 149* |
| K | 2.6 | 3.1 | 4.4 | 2.9* |
| Ca | 1.1 | 1.4 | 1.4 | 1.24* |
5. Comparison of Real and Artificial CSR Electrolyte Concentrations
| Ion/Compound | Cerebrospinal Fluid* | Artificial CSF |
|---|---|---|
| Na | 154 | 150 |
| K | 3.0 | 3.0 |
| Ca | 1.4 | 1.4 |
| Mg | 0.9 | 0.8 |
| P | 0.4 | 1.0 |
| Cl | 136 | 155 |
| HCO3 | 24.1 | -- |
(Concentration in mM)
*Note : Cerebrospinal fluid concentrations are an average of the values listed for the various animal species shown in #4 above.
1 Ion concentrations (except for the levels indicated with an asterisk) are an average of the data listed in Davson, H. Physiology of the Cerebrospinal Fluid, J. & A. Churchill, Ltd., London, 1967 and Biology Data Book , Volume III, 2nd ed., Fed. Am. Soc. Exper. Biol., Washington D.C., 1974
6. Explanation for the Absence of HCO3
Bicarbonate was not added to the formula for artificial CSF for two reasons:
- Bicarbonate can cause shifts in the pH of the solution as it converts to CO2.
- As HCO3converts to CO2 , bubbles can develop inside the pump. The presence of a gas in the pump can then affect the pumping rate in unpredictable ways.
Therefore, unless there is an urgent need for using bicarbonate in a study, we strongly recommend that it not be added to the formula for artificial CSF.
Pump Advantages
- Ensure around-the-clock exposure to test agents at predictable levels
- Permit continuous administration of short half-life proteins and peptides
- Provide a convenient method for the chronic dosing of laboratory animals
- Minimize unwanted experimental variables and ensure reproducible, consistent results
- Eliminate the need for nighttime or weekend dosing
- Reduce handling and stress to laboratory animals
- Small enough for use in mice or very young rats
- Allow for targeted delivery of agents to virtually any tissue
- Cost-effective research tool
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