A Multipurpose Four-Channel Fluid Swivel

This article describes the construction of a functional quadruple fluid swivel with low propensity to leaking and low resistance to rotation. It was obtained through the addition of a fourth channel and some modifications performed on the rotary unit of a triple channel fluid swivel recently described. Those modifications included alterations of the Touhey–Borst adapter (Becton-Dickinson), and the development of a new method of fixation of the rotary tubes to the rotary unit of the swivel using nuts and screws. With those improvements the former swivel was transformed in a still more versatile device that can be used in experimental designs requiring the use of this relatively high number of channels. It can be used, for instance, in simultaneous off-line brain microdialysis of up to four different areas or on-line brain microdialysis in two areas; in push–pull perfusions of two brain regions; in studies determining the neuropharmacokinetics and pharmacodynamics of any compound and combining continuous drug infusion through one channel, double brain microdialysis to describe the distribution characteristics of the drug into the central nervous system as well as to monitor the neurochemical modifications induced by the drug, and continuous plasma sampling to know the plasma pharmacokinetics of the drug. These and several other methods used in neuroscience research can also be combined using the swivel described here.