ABSTRACT
Transient global amnesia (TGA) is a clinical syndrome characterized by the sudden onset of an extraordinarily large reduction of anterograde and a somewhat milder reduction of retrograde episodic long-term memory. Additionally, executive functions are described as diminished. Although it is suggested that various factors, such as migraine, focal ischemia, venous flow abnormalities, and epileptic phenomena, are involved in the pathophysiology and differential diagnosis of TGA, the factors triggering the emergence of these lesions are still elusive. Recent data suggest that the vulnerability of CA1 neurons to metabolic stress plays a pivotal part in the pathophysiological cascade, leading to an impairment of hippocampal function during TGA. In this review, we discuss clinical aspects, new imaging findings, and recent clinical-epidemiological data with regard to the phenotype, functional anatomy, and putative cellular mechanisms of TGA.
ABSTRACT
In humans, drug-associated stimuli can provoke heroin relapse during abstinence. In rats, cues paired with heroin self-administration reinstate heroin seeking in a relapse model. The neurobiological mechanisms involved in this reinstatement, however, are largely unknown. Here, we determined the effect of LY379268, an mGluR2/3 agonist that decreases evoked glutamate release, on cue-induced reinstatement of heroin seeking. Systemic injections of LY379268 attenuated reinstatement of heroin seeking induced by exposure to a discrete tone-light cue that was previously paired with heroin infusions during self-administration training. In contrast, LY379268 had no effect on heroin self-administration. Results indicate that glutamate plays an important role in cue-induced reinstatement of heroin seeking and suggest that mGluR2/3 agonists should be considered for the treatment of opiate relapse.
