The activity profiles of the solubilized protein kinases from the microsomal and myelin fractions of bovine brain were examined by column chromatography and sucrose density gradient centrifugation. The main peak of adenosine 3'5'-monophosphate (cyclic AMP)-dependent activity with histone as substrate for each membrane enzyme was eluted with about 0.2hl-NaCl on a DEAE-cellulose column. A peak of activity stimulated with cyclic AMP was also eluted with about 0.1 M-N~CI for the microsomal enzyme. A peak with prolamine and casein as substrate for the microsomal or myelin enzyme, respectively. was larger than that with histone as substrate for each enzyme, The first peak with histone as substrate on a DEAE-cellulose column appeared as two peaks on the Sepharose 68 column. The second peak with histone as substrate on DEAE-cellulose cnlumn was shown to be a holoenzyme consisting of regulatory and catalytic subunits. The holoenzyme and whunits were eluted at similar positions to each other between both membrane enzymes on Sepharose 6 8 column. The holoenzyme sedimented as two peaks of activity on sucrose density gradient centrifugation, both of which were stimulated with cyclic AMP. The preincubation of the holoenzyme with cyclic AMP resulted in shifting to a position of a smaller molecular size.The results indicate the occurrence of multiple forms of protein kinases in membrane fractions of brain with respect to substrate specificity and physical property.

No abstract

No abstract

The noradrenergic terminals in the substantia gelatinosa of the dorsal horn of the cervical spinal cord of the rat were investigated by means of the histofluorescence technique and electron-microscopic cytochemistry using the glyoxylic acid-KMnO4 fixation technique. In accordance with the topographical distribution of fluorescent catecholaminergic fibers, noradrenergic terminals containing small granular vesicles were frequently observed electron microscopically in the outer layer of the substantial gelatinosa. These terminals were most frequently found to appose (without showing typical synaptic features, small-caliber dendrites, spine apparatus, and rarely, large caliber dendrites. Only in a few cases, the noradrenergic terminals exhibited typical synaptic contacts with dendritic elements of small size. In addition, noradrenergic terminals apposed non-noradrenergic terminals containing small agranular vesicles. In rats bearing surgical lesions of the dorsal roots, no noradrenergic terminal were found in contact with the degenerated axon terminals in the substantia gelatinosa. These findings suggest that the noradrenergic afferents to the substantia gelatinosa may exert their influence on sensory transmission via dorsal horn cells.

Fine structure of the noradrenaline (NA) nerve terminals in the dorsomedial portion of the nucleus tractus solitarii (NTS) was investigated by glyoxylic acid-potassium permanganate fixation method. The NA nerve terminals in this area contained a large number of small cored vesicles (SCV) (about 400-600 A in diameter) together with a few large cored vesicles (LCV) (about 1000 A in diameter). The most frequent feature of NA nerve terminals observed in this area was axo-dendritic contact. An axo-axonic contact between NA and non-NA terminals was also occasionally identified, while no axo-somatic contact was found in this area as far as examined. At the contact zone between NA terminals and other neuronal elements, the following profiles suggestive of synapse-like contact were identified: 1) somewhat dense material between contact membranes (intersynaptic filaments); 2) a slight accumulation of dense material adjacent to postcontact membranes; 3) disarrangement of contact membranes and enlargement of the space between these membranes; 4) aggregation of SCV and LCV to contact membranes. Finally it should be emphasized that NA nerve terminals often made a neuronal cluster or rosette with other neuronal elements, suggestive of a complicated role of NA on NTS function.