RELEASE OF ENKEPHALIN FROM RAT GLOBUS PALLIDUS INVITRO

SINCE the discovery of the endogenous opioid peptides Leu- and Met-enkephalin in mammalian brain, there has been considerable interest in their possible physiological functions1-3. Recent immunohistochemical studies have shown that the enkephalins are localised in neurones in various regions of the central nervous system, with high concentrations in nerve terminals4,5. These morphological studies and the results of detailed regional analyses of rat brain by radioimmunoassay have indicated that enkephalin-containing nerve terminals are particularly concentrated in the rat globus pallidus, which by radioimmunoassay has been found to contain a concentration of enkephalin six to eight times higher than that observed in any other brain region6,7. Here, we describe a calcium-dependent evoked release of enkephalin-like immunoreactivity from slices of rat globus pallidus in vitro. This finding supports the view that enkephalins may be released as neurotransmitter substances from nerve terminals in the brain. © 1978 Nature Publishing Group.