This paper describes a new low-torque, bubble-free and multiple-channel swivel of easy construction. This swivel combined with the use of fused silica capillary tubing to connect syringes and injectors, as we recently proposed, allow the accurate and repeated microinjection of low nanoliter volumes (10 nl) in freely moving rats, as required in the intracranial self-administration paradigm. Microinjections can be simultaneously performed in 3 different brain regions. Relatively large volumes in the 10-100 microliters range can be repeatedly administered, as in intravenous self-administration, using the traditional connections with polyethylene (PE) tubing. This swivel allows the execution of experiments involving in vivo microdialysis in up to 3 different brain areas. The internal channel has a very low dead space (4 microliters) and can be used to withdraw small liquid samples and perform on-line microdialysis in freely moving animals. This versatility makes the present swivel appropriate for sophisticated experimental designs involving combinations of intracranial, intravenous and/or intragastric self-administration with microdialysis.