Studies on the involvement of endogenous neuropeptides in the control of thymocyte proliferation in the rat.
The possible involvement of endogenous vasoactive intestinal peptide (VIP), cholecystokinin (CCK) and neurotensin (NT) in the control of thymocyte proliferation has been investigated in vivo in the immature rat. For this task, we have studied the effects of the administration of selective antagonists of the receptors of the three neuropeptides on the mitotic index (% of metaphase-arrested cells after vincristin injection) of thymocytes. Both CCK- and TN-receptor antagonists were ineffective. In contrast, two VIP receptor antagonists (VIP-As) enhanced the mitotic index of thymocytes. VIP reversed the effect of VIP-As, but when administered alone it did not alter the mitotic activity of thymocytes. In light of these findings, we conclude that endogenous VIP exerts a maximal tonic inhibitory influence on the basal proliferative activity of rat thymocytes, while endogenous CCK and NT do not play a relevant modulatory role in this process.
Trejter
M
M
Department of Histology and Embryology, School of Medicine, Poznan Poland.
Warchol
J B
JB
de Caro
R
R
Brelinska
R
R
Nussdorfer
G G
GG
Malendowicz
L K
LK
D000818:Animals; D002455:Cell Division; D002766:Cholecystokinin / Q000031:analogs & derivatives / Q000494:pharmacology / Q000502:physiology; D005260:Female; D008940:Mitotic Index; D009479:Neuropeptides / Q000494:pharmacology / Q000502:physiology*; D009496:Neurotensin / Q000502:physiology; D018377:Neurotransmitter Agents / Q000494:pharmacology; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011453:Prostaglandins / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011949:Receptors, Cholecystokinin / Q000037:antagonists & inhibitors; D018028:Receptors, Neurotensin / Q000037:antagonists & inhibitors; D018005:Receptors, Vasoactive Intestinal Peptide / Q000037:antagonists & inhibitors; D013601:T-Lymphocytes / Q000502:physiology*; D014660:Vasoactive Intestinal Peptide / Q000502:physiology
C495403:Adcyap1 protein, rat; D009479:Neuropeptides; D018377:Neurotransmitter Agents; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D011453:Prostaglandins; D011949:Receptors, Cholecystokinin; D018028:Receptors, Neurotensin; D018005:Receptors, Vasoactive Intestinal Peptide; D014660:Vasoactive Intestinal Peptide; D009496:Neurotensin; D002766:Cholecystokinin