ALPHA CALCIUM CALMODULIN-DEPENDENT PROTEIN-KINASE-II SELECTIVELY EXPRESSED IN A SUBPOPULATION OF EXCITATORY NEURONS IN MONKEY SENSORY-MOTORCORTEX - COMPARISON WITH GAD-67 EXPRESSION/
Eg. Jones et al., ALPHA CALCIUM CALMODULIN-DEPENDENT PROTEIN-KINASE-II SELECTIVELY EXPRESSED IN A SUBPOPULATION OF EXCITATORY NEURONS IN MONKEY SENSORY-MOTORCORTEX - COMPARISON WITH GAD-67 EXPRESSION/, The Journal of neuroscience, 14(2), 1994, pp. 611-629
In situ hybridization histochemistry and immunocytochemistry, includin
g double immunofluorescence, were used to study the populations of neu
rons expressing the alpha subunit of type II calcium/calmodulin-depend
ent protein kinase (CAM II kinase-alpha) or glutamic acid decarboxylas
e (GAD) in the somatic sensory and motor areas of the macaque monkey c
erebral cortex. Sections were subjected to in situ hybridization using
radioactive, complementary RNA probes specific for monkey CAM II kina
se-alpha or 67 kDa GAD mRNAs. Others were stained immunocytochemically
for CAM II kinase-cu and/or GABA. CAM II kinase-alpha and GAD-67 are
expressed in different populations of cells, with no colocalization. C
AM II kinase-alpha is expressed in pyramidal cells of layers II-VI, es
pecially layers II and III, as well as in certain small nonpyramidal c
ells of layer IV in areas 3a, 3b, 1, and 2 and of middle regions of ar
ea 4. Both cell types produce excitatory amino acid transmitters. Ther
efore, as in subcortical regions, CAM II kinase-alpha will be found on
the presynaptic side of excitatory synapses but on the postsynaptic s
ide only when these synapses occur on excitatory neurons in the sensor
y-motor cortex. Quantitative examination showed that CAM II kinase-alp
ha immunoreactive cells form, on average, approximately 50% of the tot
al neuronal population in each area, while GABA immunoreactive or GAD
cRNA hybridized cells form approximately 25-30%. Thus, CAM II kinase-a
lpha expressing cells cannot account for the total population of non-G
ABAergic cortical cells, and a certain proportion of the pyramidal cel
ls probably do not express it. In other cortical areas, gene expressio
n for the two molecules is regulated by afferent activity. Therefore,
the present results form a necessary basis for studies aimed at determ
ining the role of activity-dependent changes in the balance of excitat
ion and inhibition as a mechanism underlying plasticity of representat
ional maps in the primate sensory-motor cortex.