A chronically implantable arterial catheter for use in unrestrained small animals

An easily constructed arterial catheter was designed for use in experiments requiring serial blood sampling from conscious, free-moving animals (Fischer 344 rat). It can be implanted chronically, at least several days before use, into the femoral artery, without interference of movement or damage by the animal. The catheter assembly is worn subdermally until the distal portion is exteriorized for blood sampling. The proximal tip of the catheter is occluded with a removable plug before implantation, thereby eliminating the necessity of daily flushing prior to use. The catheter has been used extensively in studies of the blood-brain barrier involving the bolus injection of [14C]sucrose into the jugular vein of conscious, unrestrained rats. Tracer concentration in plasma and whole blood was subsequently determined from arterial blood samples collected serially over a 20-min period following injection of the tracer.