Cellular organization of the brain renin-angiotensin system

摘要: A model of intracellular Ang II formation (Figure 1) implies that angiotensinogen neurons exist and CNS acts both as a neurotransmitter well neurohormone. Such mechanism is consistent with the immunocytochemical localization fraction brain in neurosecretory vesicles. To date, several dozen peptide neurotransmitters neurohormones have been studied. Those assigned to peptidergic systems follow generalized pathway biosynthesis shown Figure 1. In systems, prohormone all its processing enzymes are synthesized rough endoplasmic reticulum cell move into Golgi apparatus 1: #1-3). packaged same vesicle (#3). These secretory vesicles then migrate toward plasma membrane, frequently via axonal or dendritic projections terminals. Within these cytoplasmic prior release, activated (#4) enzymatically processed, yielding active (#5-6). Only do fuse membrane (in calcium-dependent process), releasing their contents (#7-8). Once released, migrates across extracellular space interacts specific surface receptors initiate response (#9). Finally, receptor-bound degradation initiated by receptor-mediated endocytosis (#10-11). For angiotensin peptides be produced intracellularly, must present only one for packaging renin angiotensinogen; otherwise current theories protein sorting would predict two proteins segregated even if within cell. Small quantities co-packaged occurring "spill-over" between compartments seems an unsatisfactory process regulated hormone system. 2, depicting producing brain, has also proposed. The molecular information encoded component proteins, known mechanisms secretio, well-defined systemic renin-angiotensin enzymatic cascades, demonstration components system brain. This 2) allows independently coordinated gene expression synthesis (#1R), (#1A), angiotensin-converting enzyme (# 1C) different cells.(ABSTRACT TRUNCATED AT 400 WORDS)