Prenatal cocaine exposure alters alpha2 receptor expression in adolescent rats

Sex-specific alterations of α2-AR were found in the hippocampus and amygdala of the cocaine-exposed animals, as well as an upregulation of α2-AR in parietal cortex.These data suggest that prenatal cocaine exposure results in a persistent alteration in forebrain NE systems as indicated by alterations in receptor density. These neurochemical changes may underlie behavioral abnormalities observed in offspring attentional processes following prenatal exposure to cocaine.Recently, noradrenergic systems have been identified as a potential teratogenic target underlying the functional effects of prenatal cocaine [1-3]. However, information regarding the consequences of prenatal cocaine on the development of noradrenergic receptors is relatively sparse. NE is present early in brain development and regulates important aspects of prenatal brain development, including neural migration and synaptogenesis [4,5]. Thus, the ability of cocaine to inhibit NE reuptake has potentially profound effects on the developing nervous system and function of NE systems.Previous investigations into the effects of prenatal cocaine exposure on catecholaminergic receptors have, for the most part, focused on the long-term effects of exposure on dopaminergic [6-10] and serotonergic [11-14] receptor systems. Fewer studies have examined the noradrenergic receptor family following prenatal cocaine exposure. The neurophysiological effects of NE are mediated by three types of receptors: α1, α2 and β. The α2 adrenergic receptors are present very early in development, in some brain areas as early as E15 [4]. Prenatal exposure to cocaine has been found to elevate the density of α2 adrenergic receptors in the cerebellum and forebrain [15]. Henderson et al [16] reported that cortical α2 adrenergic receptor density was unchanged in male rat pups following prenatal cocaine exposure. However, these studies did not differentiate between male and female offspring and used homogenate binding techniques. Moreover, co