Liquid cation exchange extraction of cholinomimetic activity from brain

Transport of L-proline by rat brain slices

L-Proline is taken up into slices of rat cerebral cortex by a structurally specific 'high affinity' system which is absolutely dependent on sodium ions. The system mediating L-proline uptake in homogenates of cerebral cortex is associated with osmotically sensitive particles of the same equilibrium density as synaptosomes. Based on tissue-medium ratios, the uptake of L-proline is most efficient in slices of cerebral cortex and of hypothalamus, and least efficient in slices of cerebellum. L-Proline taken up into slices of cerebral cortex can be released from these slices by an increased potassium ioort into and out of brain slices are consistent with L-proline functioning as a synaptic transmitter in that they are analogous to observations on the transport of transmitter amino acids such as GABA.

Isolation of choline esters from aqueous solutions by extraction with sodium tetraphenylboron in organic solvents

1. The method is based on the observation that choline esters and sodium tetraphenylboron (Kalignost) form complexes that are insoluble in water but soluble in organic solvents such as nitriles, higher ketones and benzyl alcohol. 2. The extraction procedure is an example of liquid cation exchange where tetraphenylboron is the cation-exchange group. 3. The proportion of choline esters extracted depends on the type and total amount of cation in the aqueous phase and the amount of sodium tetraphenylboron in the organic solvent. 4. The proportion of choline esters extracted is independent of the choline ester concentration, the pH (between 8 and 3) and the relative volumes of the two phases. 5. The affinity of sodium tetraphenylboron for choline esters increases with an increase in the size of the acyl group. 6. The choline ester extracted can be released into an aqueous solution by treatment with strong acids, silver salts and anion-exchange resins.