ISSN:
1432-0878
Keywords:
Mouse adrenal medulla
;
Chromaffin cells
;
SGC cells
;
Morphine effects on catecholamines
;
Biochemical and ultrastructural correlation
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The effects of morphine on chromaffin cell ultrastructure and catecholamine contents were studied using the adrenal glands from male mice (ICR strain). After 2 h adrenaline was increased 25% from 8.1 to 11.6 μmol/g tissue, followed by a 50% decrease to 5.2 μmol/g between 8–24 h and low values persisting at 72 h. Dopamine increased initially, reaching peak values of 0.5 μmol/g between 8–24 h, but had returned towards control values of 0.29 μmol/g by 72 h. Noradrenaline remained unchanged at 2.5 μmol/gram. Naloxone prevented alterations in adrenaline and dopamine levels. Ultrastructural examination revealed several types of catecholamine-storing cells. Of these the adrenaline and small-granule chromaffin (SGC) cells were more affected by morphine than noradrenaline cells. While the initial elevation of adrenaline 2 h after morphine was not accompanied by significant ultrastructural changes, the decrease after 8 and 24 h was paralleled by a significant (p〈0.001) loss of adrenaline granules. Signs of active membrane turnover included an increase in the number of vacuoles, and the appearance of numerous coated omega profiles and coated (77.7±0.6 nm) vesicles. Clusters of synaptic-like vesicles (59.8±8.2 nm), slightly larger than neuronal vesicles (45.4±6.4), increased in the SGC-cells. After 72 h, the chromaffin granules in adrenaline cells remained low in numbers and were heterogeneous in electron density. Many synapticlike vesicles were aligned along the SGC-cell membranes where only few chromaffin granules (109.3±20 nm) remained. Thus, continuous morphine exposure for 8–72 h increases the turnover of storage granules in adrenaline and SGC-cells with less effect on the noradrenaline cells which maintain catecholamine levels as indicated by biochemical analysis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00216513
