{'fraction_non_alphanumeric': 0.040096230954290296, 'fraction_numerical': 0.03207698476343224, 'mean_word_length': 5.709677419354839, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
MECHANISMS FOR THE EFFLUX OF [14C]DOPA AND [14C]DOPAMINE FROM THE CSF OF RHESUS MONKEYS

—Clearance of [14C]DOPA and [14C]dopamine from CSF was investigated in anaesthetized rhesus monkeys (M. Mulatta) subjected to ventriculocisternal perfusion. The efflux coefficients, kVE, at tracer concentrations (3–5 m) in the perfusate were 0.0487 ml/min and 0.0325 ml/min for [14C]DOPA and [14C]dopamine, respectively. Carrier DOPA (10 mm) in the perfusate decreased the efflux of [14C]DOPAsignificantly, but carrier dopamine had no appreciable effect on the clearance of [14C]dopamine. These findings suggest that DOPA is cleared from CSF in part by a saturable mechanism which may be located in the choroid plexus, whereas dopamine leaves the ventricular system by passive diffusion. Radioactivity in the caudate nucleus immediately adjacent to the perfused ventricle averaged 15.5 % and 12.6% of the radioactivity in the perfusates with [14C]DOPA or [14C]dopamine, respectively. These distribution percentages were similar to those found for various extracellular indicators after ventriculocisternal perfusion and may indicate that the efflux of intraventricularly‐administered exogenous DOPA and dopamine occurs in part through extracellular channels.