Matteoli M, Haimann C, Torri-Tarelli F, Polak J M, Ceccarelli B, De Camilli P
Consiglio Nazionale delle Ricerce Center of Cytopharmacology, University of Milano, Italy.
Proc Natl Acad Sci U S A. 1988 Oct;85(19):7366-70. doi: 10.1073/pnas.85.19.7366.
The regulatory peptide called calcitonin gene-related peptide (CGRP) was detected by immunofluorescence in frog motor neurons and motor nerve terminals. In motor nerve terminals, CGRP-like immunoreactivity was found to be segregated within large dense-core vesicles. To determine whether exocytosis from acetylcholine-containing small synaptic vesicles and from CGRP-containing large dense-core vesicles can be independently stimulated, nerve-muscle preparations were exposed to alpha-latrotoxin. This toxin induced complete depletion of acetylcholine-containing small synaptic vesicles but did not induce a parallel depletion of CGRP-like immunoreactivity and of large dense-core vesicles. These effects were independent of the presence of extracellular Ca2+ and occurred both at room temperature and at low temperature (1-3 degrees C). These findings suggest that exocytosis from the two vesicle populations is mediated by distinct biochemical mechanisms, which might be differentially regulated by physiological stimuli.
通过免疫荧光法在青蛙运动神经元和运动神经末梢中检测到了一种名为降钙素基因相关肽（CGRP）的调节肽。在运动神经末梢中，发现CGRP样免疫反应性定位于大型致密核心囊泡内。为了确定含乙酰胆碱的小突触囊泡和含CGRP的大型致密核心囊泡的胞吐作用是否能被独立刺激，将神经-肌肉标本暴露于α-银环蛇毒素。这种毒素导致含乙酰胆碱的小突触囊泡完全耗尽，但并未导致CGRP样免疫反应性和大型致密核心囊泡的平行耗尽。这些效应与细胞外Ca2+的存在无关，在室温及低温（1-3摄氏度）下均会发生。这些发现表明，来自这两种囊泡群体的胞吐作用是由不同的生化机制介导的，这些机制可能受到生理刺激的不同调节。
