Effect of nitric oxide donors on the central nervous system--nitroglycerin studies in the rat

The demonstration that nitrovasodilators act as nitric oxide (NO) donors has favored a resurgence of interest in this class of compounds. The demonstration of the different biological effects of NO in various districts, including the central nervous system, suggests a possible role for these substances besides their well-known cardiovascular activity. Among the various nitrovasodilators commercially available, nitroglycerin represents a well known substance to headache experts because of its capability to provoke spontaneous-like migraine attacks in headache-free migrainous subjects. Basic research has recently demonstrated that nitroglycerin activates a variegate set of brain nuclei following systemic administration via the intervention of selected neurotransmitters and neuromediators, with a specific time-pattern in different brain areas. Increasing evidence suggests that nitroglycerin-induced neuronal activation is mediated by multiple mechanisms that include direct neuronal and vascular action of nitroglycerin-derived and endogenously-synthesized NO, as well as indirect effects related to nitroglycerin-induced changes in cardiovascular and trigeminovascular systems. The study of the neurovascular effects of nitroglycerin in the rat provides relevant information for a better understanding of the pathophysiology of migraine attacks and of their triggers.