Sympathetic influence on transport functions in the choroid plexus of rabbit and rat

In vitro uptake of an organic base (choline) and an organic acid (p-aminohippuric acid; PAH), both radiolabelled, was measured in isolated choroid plexus of rat and rabbit, and expressed as tissue/medium ratios. A significant increase in the tissue accumulation of choline was seen in denervated rabbit choroid plexus 1 week following unilateral cervical sympathectomy. The accumulation of PAH was not affected. The uptake of both test substances was significantly reduced after sympathetic denervation of the rat choroid plexus. The results agree with the local sympathetic inhibition of cerebrospinal fluid production in rabbit (corresponding studies on rat have not been performed), and favour the assumption that the adrenergic nerves in the choroid plexus mediate direct effects on the plexus epithelium.