Proinsulin C peptide obviates sympathetically mediated suppression of splenic lymphocyte activity in rats.
OBJECTIVE
To investigate whether proinsulin C peptide influences sympathetic nerve activity directly or indirectly through parasympathetic nerve activity.


METHODS
The proliferative response of splenic lymphocytes to Concanavalin A (ConA response) which is known to be suppressed by subjection of rats to footshock or intracerebroventricular injection of corticotropin-releasing factor through sympathetic nerve activation was measured. Effect of C peptide alone or before subjection to footshock or injection of corticotropin-releasing factor was examined.


RESULTS
Intraperitoneal injection of C peptide was without effect on the basal ConA response, while subjection to footshock or injection of corticotropin-releasing factor lowered it. In contrast, prior injection of C peptide obviated the footshock and corticotropin-releasing factor-induced suppression of the response. When given intracerebroventricularly, C peptide was also effective at much smaller doses. Prior injection of atropine cancelled the C-peptide effects.


CONCLUSIONS
Our results indicate that C peptide counteracts the sympathetic nerve-mediated suppression of splenic lymphocyte proliferation in an atropine-sensitive manner. Thus, C peptide probably activates the parasympathetic nervous system through the afferent mechanism, that in turn antagonizes the sympathetic nerve-mediated suppression of splenic lymphocyte functions.
Okamoto
S
S
Department of Biomedical Sciences, Graduate School of Veterinary Medicine, Hokkaido University, Japan.
Kimura
K
K
Kitamura
T
T
Cañas
X
X
Yoshida
T
T
Saito
M
M
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002096:C-Peptide / Q000008:administration & dosage / Q000494:pharmacology*; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology; D004597:Electroshock; D005260:Female; D006801:Humans; D007165:Immunosuppression Therapy; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D008213:Lymphocyte Activation / Q000187:drug effects*; D008214:Lymphocytes / Q000187:drug effects / Q000276:immunology*; D051381:Rats; D017208:Rats, Wistar; D013154:Spleen / Q000276:immunology / Q000294:innervation*; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*
D002096:C-Peptide; D001285:Atropine; D003346:Corticotropin-Releasing Hormone