Cholecystokinin increases cytosolic calcium in a subpopulation of cultured vagal afferent neurons |
| |
Authors: | Simasko Steven M Wiens Jason Karpiel Adrienne Covasa Mihai Ritter Robert C |
| |
Affiliation: | Program in Neuroscience, Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, College of Veterinary Medicine, Washington State University, Pullman, Washington 99164, USA. simasko@vetmed.wsu.edu |
| |
Abstract: | Imaging fluorescent measurements with fura 2 were used to examine cytosolic calcium signals induced by sulfated CCK octapeptide (CCK-8) in dissociated vagal afferent neurons from adult rat nodose ganglia. We found that 40% (184/465) of the neurons responded to CCK-8 with a transient increase in cytosolic calcium. The threshold concentration of CCK-8 for inducing the response varied from 0.01 to 100 nM. In most neurons (13/16) the response was eliminated by removing extracellular calcium. Depleting intracellular calcium stores with thapsigargin slightly augmented the response. Most neurons were unresponsive to nonsulfated CCK-8. The response was eliminated by the CCK-A receptor antagonist lorglumide. Low concentrations of JMV-180 had no effect; however, high concentrations of JMV-180 reduced responses to CCK-8. These results demonstrate that CCK acts at the low-affinity site of the CCK-A receptor to trigger the entry of extracellular calcium into vagal afferent neurons. Increased cytosolic calcium may participate in acute activation of vagal afferent neurons, or it may initiate long-term changes, which modulate future neuronal responses to sensory stimuli. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|