Lack of asymmetrical distribution of receptor binding sites and of neurally active peptides within rat brain.

The high affinity binding of 5 tritiated (naloxone, spiroperidol, serotonin, quinuclidinylbenzilate, dihydroalprenolol) ligands to left and right frontal cortex, hippocampus and striatum has been compared in 8-week-old male rats. No lateralization of specific binding was observed between paired brain regions. Also, no regional asymmetry of protein content was found. No significant differences in met-enkephalin and substance P contents were found between paired striata, frontal cortex, and hippocampi. These data suggest that several neurotransmitter and neuromodulator indices are symmetrically distributed within the rat brain.