POSTNATAL-DEVELOPMENT OF NEUROGENIC INFLAMMATION IN THE RAT

We have studied the development in the rat of neurogenic inflammatory mechanisms that mediate cutaneous plasma extravasation. At birth and at postnatal day 10, intradermal injection of substance P, histamine, and bradykinin produced no significant plasma extravasation. At day 13 through adulthood (days 42-49), all test agents produced significant plasma extravasation which increased with increasing age. In the adult rat, pretreatment with 6-hydroxydopamine, to eliminate sympathetic postganglionic nerve terminals, attenuated the plasma extravasation elicited by substance P, histamine and bradykinin. The possible role of the sympathetic postganglionic neuron in the age-dependent changes in neurogenic inflammation is discussed.