Related Experiment Videos
Stimulatory effect of vasoactive intestinal peptide (VIP) on cyclic AMP production in rat peritoneal macrophages
J J Segura1, J M Guerrero, R Goberna
1Departamento de Bioquímica Médica y Biología Molecular, Facultad de Medicina, Universidad de Sevilla, Spain.
Abstract:
Vasoactive intestinal peptide (VIP) stimulated cyclic AMP production in rat peritoneal macrophages. The stimulatory effect of VIP was dependent on time, temperature and cell concentration, and was potentiated by the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX). At 15 degrees C, the response occurred in the 0.1-1000 nM range of VIP concentrations. Half maximal stimulation of cellular cyclic AMP (ED50) was obtained at 1.2 +/- 0.5 nM VIP, and maximal stimulation (about 3-fold basal level) was obtained between 100-1000 nM. The cyclic AMP system of rat peritoneal macrophages showed a high specificity for VIP. The order of potency observed in inducing cyclic AMP production was VIP greater than rGRF greater than hGRF greater than PHI greater than secretin. Glucagon, insulin, pancreastatin and octapeptide of cholecystokinin did not modify cyclic AMP levels at concentrations as high as 1 microM. The beta-adrenergic agonist isoproterenol increased the cyclic AMP production and show additive effect with VIP. Somatostatin inhibits the accumulation of cyclic AMP in the presence of both vasoactive intestinal peptide and isoproterenol. The finding of a VIP-stimulated cyclic AMP system in rat peritoneal macrophages, together with the previous characterization of high-affinity receptors for VIP in the same cell preparation, strongly suggest that VIP may be involved in the regulation of macrophage function.
Insights
Vasoactive intestinal peptide (VIP) stimulates cyclic AMP production in rat macrophages. This suggests VIP plays a role in regulating macrophage immune functions.
Area of Science:
- Immunology
- Cell Biology
- Neuroendocrinology
Background:
- Vasoactive intestinal peptide (VIP) is a neuropeptide with diverse physiological roles.
- Macrophages are key immune cells involved in host defense and inflammation.
- The role of VIP in modulating macrophage function is not fully understood.
Purpose of the Study:
- To investigate the effect of VIP on cyclic AMP (cAMP) production in rat peritoneal macrophages.
- To characterize the specificity and potency of VIP-induced cAMP signaling.
- To explore the potential involvement of VIP in macrophage regulation.
Main Methods:
- Primary culture of rat peritoneal macrophages.
- Measurement of intracellular cAMP levels using radioimmunoassay or luminescence assays.
- Dose-response studies with VIP and related peptides.
- Assessment of interactions with other signaling molecules like IBMX, isoproterenol, and somatostatin.
Main Results:
- VIP significantly stimulated cAMP production in a time-, temperature-, and dose-dependent manner.
- The ED50 for VIP-induced cAMP stimulation was 1.2 +/- 0.5 nM, with maximal stimulation at 100-1000 nM.
- Macrophage cAMP system exhibited high specificity for VIP over other related peptides.
- Isoproterenol showed additive effects with VIP, while somatostatin inhibited VIP-induced cAMP accumulation.
Conclusions:
- VIP potently stimulates cAMP production in rat peritoneal macrophages.
- These findings, coupled with known VIP receptors, suggest VIP is a regulator of macrophage function.
- VIP signaling may represent a novel target for modulating immune responses.