Comparison of the size of neuronal and non-neuronal histamine pools in the brain of different rat strains.

The size of the neuronal and non-neuronal histamine pools in the brain of three different strains of rats was measured by assuming that the alpha-fluoromethylhistidine-induced maximal decrement of histamine represents the size of the neuronal pool. Although the total histamine levels in the brain showed a considerable interstrain variation, no significant interstrain difference was observed in the neuronal histamine level. These results suggest that the size of the neuronal histamine pool in the brain is relatively stable, whereas the size of the non-neuronal histamine pool is variable.