Systemic nitroglycerin activates peptidergic and catecholaminergic pathways in rat brain.

In this study, we carried out an immunohistochemical evaluation of the neurochemical characteristics of neurons that are activated (i.e., express Fos protein) in response to systemic administration of nitroglycerin. In the brain stem, a significant percentage of activated neurons contained noradrenaline as a neurotransmitter, whereas only a few of them contained serotonin. In the paraventricular and supraoptic nuclei of the hypothalamus, numerous Fos-immunoreactive neurons were also positive for vasopressin, oxytocin, and corticotropin-releasing factor. Codistribution with corticotropin-releasing factor was also observed in the central nucleus of the amygdala. Our findings point out a prominent role for catecholaminergic and peptidergic pathways in the brain in response to systemic nitroglycerin.