DISTRIBUTION OF 6 TRANSPLASMA MEMBRANE NADH-DEHYDROGENASES IN RAT-BRAIN TISSUE

Transplasma membrane redox plays a significant role in cellular activa tion and growth. Six isoenzymes could be prepared from purified rat br ain synaptic plasma membrane. Polyclonal antibodies have been prepared against six transplasma membrane oxydoreductases (PMO-I to PMO-VI) an d the tissue distribution of the various iso-enzymes have been investi gated in adult rat brains by means of immunohistochemistry. PMO-I is d ensely observed in layers I, TV and V of the parietal cortex, in CA1 o f the hippocampus (except for the molecular layer), in the caudate put amen, in the dorsal, granular and ventral parts of the auditory nuclei , in some loci of the vestibular nuclei as well as in the deep cerebel lar nucleus and in the granular layer of the cerebellar cortex. PMO-II is mainly located in the polymorphic layer of the dendate gyrus and i n the deep cerebellar nucleus and in the granular layer of the cerebel lar cortex. PMO-III is abundant in the piriform cortex, in the pyramid al layers of both CA1 and CA2, in the diagonal band of the basal gangl ia, in the supraoptic nucleus and in various loci of the magnetocellul ar paraventricular nucleus of the hippothalamus as well as in the vest ibular nuclei from the brain stem. In addition PMO-III is also densely present in motor nuclei (oculomotor, facial, hypoglossal and ambiguus nuclei), in the reticular formation and in the deep cerebellar nucleu s as well as in the Purkinje layer of the cerebellar cortex. PMO-IV ha s a similar location but is less abundant in the vestibular nuclei of the sensory brain stem and in the motor nucleus. PMO-V in contrast is poorly present in most brain areas compared to the other iso-enzymes, apart of the Purkinje layer of the cerebellar cortex. Finally PMO-VI i s mainly present in the oriens layer and in the stratum radiatum of th e hippocampus formation, in the supraoptic and lateral magnocellular n ucleus of the hypothalamus, in the mesencephalic trigeminal nucleus, i n the ventral auditory nucleus and in the facial nucleus of the brain stem as well as in red nucleus of the reticular formation and in the P urkinje layer of the cerebellar cortex. These data show that the iso-e nzymes are located in specific brain nuclei. The significance of the r esults in respect to the yet very poorly defined function of PMO's is discussed.