Role of substance P (SP) in development of symptoms of neurogenic inflammation in the oral mucosa of the rat.
In the present series of investigations we first studied the local effects of exogenous substance P (SP) on the hallmarks of neurogenic inflammation, i.e. vascular permeability and blood flow, in the oral mucosa of the rat. Pretreatment with capsaicin was shown to attenuate the symptoms of neurogenic inflammation; therefore, the distribution of nerve fibers displaying substance P-like immunoreactivity (SP-IR) in the mandibular mucosa was also assessed in control rats and in animals pretreated with capsaicin both neonatally and in adulthood using immunohistochemical techniques. The application of SP at a dose of 7.5 nmol resulted in an almost 70% increase of vascular permeability (NS) and the administration of a four-fold higher dose (30 nmol) produced about 150% increase in Evans blue extravasation compared with control values (p < 0.05). A similar increase (ca 146%) in vascular permeability was observed in response to 45 nmol SP solution (p < 0.05). While the 7.5 nmol SP-solution failed to affect blood flow, the 30 nmol SP significantly increased it by ca. 38% (p < 0.05). The administration of the 45 nmol SP solution resulted in a similar enhancement of blood flow (43%, p < 0.05). Capsaicin pretreatment performed either neonatally or in adulthood has reduced the number of SP-immunoreactive fibers in the oral mucosa. Our functional results suggest that SP may have a role in the experimentally-induced neurogenic inflammation of the oral mucosa in the rat. This is also supported by our finding that capsaicin pretreatment, known to decrease the number of SP-immunoreactive fibers in these tissues, reduced the symptoms of neurogenic inflammation.
Györfi
A
A
Department of Pathophysiology, Semmelweiss University of Medicine, Budapest, Hungary.
Fazekas
A
A
Irmes
F
F
Jakab
G
G
Sütö
T
T
Rosivall
L
L
D000704:Analysis of Variance; D000818:Animals; D002199:Capillary Permeability / Q000187:drug effects*; D002211:Capsaicin / Q000494:pharmacology; D003238:Connective Tissue / Q000098:blood supply / Q000294:innervation; D005891:Gingivitis / Q000503:physiopathology*; D007150:Immunohistochemistry; D008297:Male; D009061:Mouth Mucosa / Q000098:blood supply* / Q000294:innervation; D051381:Rats; D017208:Rats, Wistar; D013373:Substance P / Q000494:pharmacology / Q000502:physiology*
D013373:Substance P; D002211:Capsaicin