Intravenous sodium lactate decreases plasma GABA levels in man

Lactate: a prospective target for therapeutic intervention in psychiatric disease

ABSTRACT

Although antipsychotics that act via monoaminergic neurotransmitter modulation have considerable therapeutic effect, they cannot completely relieve clinical symptoms in patients suffering from psychiatric disorders. This may be attributed to the limited range of neurotransmitters that are regulated by psychotropic drugs. Recent findings indicate the need for investigation of psychotropic medications that target less-studied neurotransmitters. Among these candidate neurotransmitters, lactate is developing from being a waste metabolite to a glial-neuronal signaling molecule in recent years. Previous studies have suggested that cerebral lactate levels change considerably in numerous psychiatric illnesses; animal experiments have also shown that the supply of exogenous lactate exerts an antidepressant effect. In this review, we have described how medications targeting newer neurotransmitters offer promise in psychiatric diseases; we have also summarized the advances in the use of lactate (and its corresponding signaling pathways) as a signaling molecule. In addition, we have described the alterations in brain lactate levels in depression, anxiety, bipolar disorder, and schizophrenia and have indicated the challenges that need to be overcome before brain lactate can be used as a therapeutic target in psychopharmacology.

GABAergic function in detoxified heroin addicts: relationship to anxiety disorders

The function of the GABAergic system was examined in 20 subjects with heroin dependence and abuse, 2 months after detoxification, and in 10 healthy volunteers, by measuring the growth hormone (GH) response to a challenge with the GABA B receptor agonist baclofen. Ten heroin addicts had comorbid anxiety disorder (Group A), while the other ten had heroin addiction uncomplicated by Axis I and II psychopathologies (Group B). GH responses to baclofen stimulation of Group A patients were significantly blunted, while those of Group B subjects did not differ from responses of healthy volunteers. Our data show that the function of the GABAergic system is impaired only in heroin addicts with comorbid anxiety disorders (anxious cluster), suggesting that the GABA system is not persistently influenced by prolonged exposure to opioid receptor stimulation.