Effects of α- and β-adrenergic receptor antagonists on retrograde amnesia produced by frontal cortex stimulation

Abstract

This study assessed the effects of adrenergic antagonists on the development of retrograde amnesia. Animals were trained on either a one-trial inhibitory (passive) avoidance task or a visual discriminated avoidance Y-maze. Thirty minutes prior to training animals received an injection of the β-adrenergic antagonists propranolol (0.5 mg/kg), saline, or one of the following α -adrenergic antagonists: phentolamine (10 mg/kg), piperoxane (5 mg/kg), or phenoxybenzamine (2 mg/kg). Shortly after training, the animals received frontal cortex stimulation (5 mA/1 sec) through implanted cortical screw electrodes. The results indicate that pretreatment of rats with any of these α - and β -adrenergic antagonists attenuates the production of retrograde amnesia. These findings add further support to the view that an adrenergic response to amnestic treatments may be a component of a restricted set of biological systems that are involved in retrograde amnesia.