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Tính chất tế bào và phân tử của một tế bào thần kinh peptidergic (neurosecretory cell) được hiển thị. Cấu trúc của tế bào neurosecretory được mô tả sơ đồ với ghi chú của các quá trình tế bào sinh học khác nhau xảy ra trong từng lĩnh vực địa hình. | Chapter 14 Posterior Pituitary Hormones 213 Fig. 3. Peptidergic neuron. Cellular and molecular properties of a peptidergic neuron neurosecretory cell are shown. The structure of the neurosecretory cell is depicted schematically with notations of the various cell biologic processes that occur in each topographic domain. Gene expression protein biosynthesis and packaging of the protein into large dense-core vesicles LDCVs occurs in the cell body where the nucleus rough ER RER and Golgi apparatus are located. Enzymatic processing of the precursor proteins into the biologically active peptides occurs primarily in the LDCVS see inset often during the process of anterograde axonal transport of the LDCVS to the nerve terminals on microtubule tracks in the axon. Upon reaching the nerve terminal the LDCVS are usually stored in preparation for secretion. Conduction of a nerve impulse action potential down the axon and its arrival in the nerve terminal cause an influx of calcium ion through calcium channels. The increased calcium ion concentration causes a cascade of molecular events that leads to neurosecretion exocytosis . Recovery of the excess LDCV membrane after exocytosis is performed by endocy-tosis but this membrane is not recycled locally and instead is retrogradely transported to the cell body for reuse or degradation in lysosomes. ATP adenosine triphosphate ADP adenosine 5 -diphosphate GTP guanosine 5 - triphosphate TGN trans-Golgi network SSV small secretory vesicles PC1 or PC2 prohormone convertase 1 or 2 respectively CP-H carboxypeptidase H PAM peptiylglycine -amidating monooxygenase. Reproduced with permission from Burbach et al. 2001 . 214 Part IV Hypothalamic-Pituitary prepro-AVP-NPII 2 5kb 20p13 prepro-vasopressin 164 a.a. signal . peptide Ỵ- provasopressin IAVPị- Gly-Lys-Arg neurophysin II - Arg glycopeptide I _ . r 3 products from AVP - NH2 I neurophysin II I I glycopeptide I the prohormone addition of a carbohydrate chain Fig. 4. Structure of the human .
