The effects of nitrous oxide on the secretory activity of pro-opiomelanocortin peptides from basal hypothalamic cells attached to cytodex beads in a superfusion in vitro system

Dispersed cells from adult rat basal hypothalami, attached to Cytodex-3 microcarrier beads, were placed in a column and superfused with aerated high glucose media or media enriched with variable concentrations of nitrous oxide with oxygen. β-Endorphin and α-MSH content was measured in the effluent collected during superfusion and demonstrated a near constant baseline release. Nitrous oxide, 60% (P < 0.025) and 80% (P < 0.02), caused significant increases in release of β-endorphin. Potassium chloride (50 mM) caused a significant increase in release (P < 0.007) of β-endorphin whereas saline and 30% nitrous oxide did not. Neither nitrous oxide-enriched media nor potassium chloride had any statistically significant effect on α-MSH release. The increase in β-endorphin secretory activity during exposure to nitrous oxide demonstrates that nitrous oxide may have a stimulatory effect on central pro-opiomelanocortin neurons.