CSF formation/inhibition
From WikiCNS
- CSF absorption is a sensitive function of intracranial pressure; absorption increases at pressures above the threshold for absorption and no absorption occurs below this threshold pressure (a linear fashion even in hydrocephalics who have the same relationship but at a reduced pressure/volume slope)
- absorption of CSF appears to be limited to the arachnoid villi
- CSF production is thought to be relatively insensitive to pressure
- CSF production is mainly in the choroid plexus although not entirely since fourth ventricle tumors that preclude communication between the ventricle and the thecal sac do not create a dry thecal sac; similarly, removing the choroid plexus of hydrocephalic patients does not cure hydrocephalus; thus epenymal cells also contribute to CSF production
- drugs that inhibit Na transport or carbonic anhydrase activity also inhibit CSF production; with various drug combinations, CSF production can be reduced to 60% of baseline
- Agents affecting CSF production – in general what increases CBF increases CSF production
- Anesthetic agents
- Halothane, ketamine – increase CSF production
- thiopental – decreases CSF production, decreases CBF, CMRO2 and is a cardiovascular depressant
- Active transport inhibitors
- Acetazolaminde, furosemide – reduce CSF production
- Hormones
- Angiotensin, vasopressin – reduce CSF production
- Others
- CO2 – increase CSF production
- Glycerol – reduces CSF production
- Norepinephrine – reduces CSF production
- CSF infection – reduces CSF production
- Aging – reduces CSF production
- Prolonged hypocapnia – no effect CSF production
- Hydrocephalus – no effect on CSF production
- Anesthetic agents