Synthesis of proteolipid by subcellular fractions from rat brain

Preparation of purified perikaryal and synaptosomal mitochondrial fractions from relatively small hypothalamic brain samples

In order to measure the activity of neuronal mitochondria, a representative proof of neuronal processes, physiologically relevant mitochondrial samples need to be gained as simply as possible. Existing methods are, however, either for tissue samples of large size and/or homogenous microstructures only, or are not tested for mitochondrial function measurements. In the present article we describe a gradient fractionation method to isolate viable and well-coupled mitochondria from relatively heterogeneous histological microstructures such as the hypothalamus. With this new method, we are able to isolate a sufficient amount of functional mitochondria for determination of respiratory activity, in a short period of time, using affordable equipment. •Verified by electron microscopy, our method separates highly enriched and well-preserved perikaryal and synaptosomal mitochondria. Both fractions contain minimal cell debris and no myelin. Respiratory measurements (carried out by Clark-type electrode) confirmed undisturbed mitochondrial function providing well-evaluable records. The demonstrated protocol yields highly viable mitochondrial subfractions within 3 h from small brain areas for high-precision examinations. Using this procedure, brain regions with relatively heterogeneous histological microstructure (hypothalamus) can also be efficiently sampled.•Up to our present knowledge, our method is the shortest available procedure with the lowest sample size to gain debris-free, fully-viable mitochondria.

Subcellular distribution of coronary dilatatory protein-hormonal complexes in rat hypothalamus

We previously reported the presence of a group of coronary dilatatory protein-carriers of the cardioactive neurohormones and precursors of bioactive compounds in the hypothalamus of some animals. Investigation of the subcellular distribution of those proteins revealed their localization in neurosecretory granules and in synaptosomes of the hypothalamus. In further investigation of the regional distribution of coronary-active proteins in different parts of the brain they were found in synaptosomes of the cerebral cortex too. The main location of coronary-active proteins in synaptosomes indicates their participation in synaptic functions.

Amino acid incorporation into brain subcellular fractions in experimental allergic encephalomyelitis

The in vitro protein synthetic capactiy of brain slices from guinea-pigs in the late stage (17-18 days post-induction) of experimental allergic encephalomyelitis was increased over that of Freund's adjuvant injected controls, as determined by the rate of (14C)-leucine incorporation into both tris-soluble and tris-insoluble proteins. All subcellular fractions prepared from incubated slices showed increased incorporation, with a crude nuclear fraction having the largest increase. Isolated brain mitochondria from EAE animals incorporated more amino acid into protein during the late stage of the disease, while isolated microsomes and "pH5 enzymes" show decreased amino acid incorporation compared with controls in the late stage of EAE. Polyacrylamide gel electrophoresis of acidic, soluble proteins isolated from (3H)-leucine labeled nuclear or synaptosomal fractions revealed that increases of incorporation were generalized, and not restricted to a few proteins.