The main purpose of this study is to define the maximum effect oxytocin (naturally occurring
hormone that is made in the brain) has on pain from a 5 minute heat probe applied to the skin
and to get an estimate for the relationship between the amount of pain relief at different
amounts of oxytocin in the blood.
This is a study of participants that will receive an intravenous (IV) infusion of oxytocin
(naturally occurring hormone that is made in the brain) with blood samples taken thereafter
in order to create a formula to describe the concentrations of oxytocin in the blood over
time (pharmacokinetics).
In this study healthy volunteers and people with knee arthritis so severe that there is a
need for a joint replacement are recruited for a one day study. Each study participant will
have 2 IV catheters placed (one in each arm). After placement of the IV catheters, 4
different levels of oxytocin will be given by IV infusion. Blood samples will be taken before
the infusion begins and after each different level of the infusion. The blood will be drawn
through the second IV catheter.
The study team will also do some tests to get a rough idea of how oxytocin changes
perceptions on the skin and how this relates to the amount of oxytocin in the blood at the
same time. The study team will study a painful perception by placing a probe on the skin and
heating it to 113 degrees Fahrenheit for 5 minutes. Each study participant will score any
pain that is experienced on a 0 to 10 scale.