Effects of capsaicin treatment on immunoglobulin secretion in the rat: further evidence for involvement of tachykinin-containing afferent nerves.
Neonatal capsaicin treatment has previously been shown to diminish the primary antibody response of adult rats to the subcutaneously administered T-dependent antigen, sheep red blood cells, as measured using a modification of the Cunningham plaque-forming cell assay technique. We have now studied the kinetics of this response in adult normal, neonatally capsaicin-pretreated and neonatally capsaicin-pretreated substance P-infused rats, and examined the effects of the tachykinin antagonist Spantide, on the plaque-forming cell response. Capsaicin pretreatment did not affect the antigen-specific plaque-forming cell response over the first 4 days following antigen injection. At days 5, 6 and 7 of the response, there was a statistically significant decrease in the number of plaque-forming cells secreting antigen-specific IgM, an effect not observed in capsaicin-pretreated rats which were given a subcutaneous infusion of substance P at the time of antigen injection. The tachykinin antagonist Spantide inhibited the plaque-forming cell response in normal rats after in vivo infusion at the time of antigen injection by more than 70%. This effect of Spantide was dose dependent, occurred with maximal effect at 10 microM, and appeared to be independent of any histamine-mediated action. The results of this study provide further evidence for a receptor-mediated immunomodulatory role of tachykinin-containing primary afferent nerves.
University of Melbourne Department of Medicine, Royal Melbourne Hospital, Parkville, Australia.
A
A
Eglezos
P V
PV
Andrews
R L
RL
Boyd
R D
RD
Helme
D000818:Animals; D000938:Antigen-Presenting Cells / Q000166:cytology / Q000187:drug effects; D002211:Capsaicin / Q000494:pharmacology*; D002452:Cell Count; D005260:Female; D006632:Histamine / Q000494:pharmacology; D007074:Immunoglobulin G / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D007136:Immunoglobulins / Q000378:metabolism*; D007700:Kinetics; D009475:Neurons, Afferent / Q000378:metabolism / Q000502:physiology*; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013373:Substance P / Q000031:analogs & derivatives / Q000494:pharmacology; D015320:Tachykinins / Q000378:metabolism*
D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007136:Immunoglobulins; D015320:Tachykinins; D013373:Substance P; D006632:Histamine; C042867:spantide; D011738:Pyrilamine; D002211:Capsaicin