The GABAA receptor antagonist picrotoxin induces a 'pain-like' behavior when administered into the thalamic reticular nucleus of the behaving rat: a possible model for 'central' pain?

In this study, we reported that the microinjection of the GABAA antagonist picrotoxin into the rat thalamic reticular nucleus produced a 'pain-like' behavior. This behavior was primarily characterized by repetitive lifting off the hindpaw from the floor contralateral to the injection site, sometimes accompanied by extension of the leg and maximal fingers separation. Surprisingly, these manifestations were not occurring when picrotoxin was applied to the ventrobasal complex itself, alternatively producing 'wet-dog' shakes. These data show that the local administration of picrotoxin is a relevant approach for studying pain of 'central' origin and complex GABAergic modulatory mechanisms within the thalamic sensory complex.