Metabolism of 3H-noradrenaline released from isolated rat hypothalamus by extracts of black widow spider glands.

In the isolated rat hypothalamus preincubated with 3H-noradrenaline, an extract from the venom glands of Latrodectus mactans elicited on overflow of tritium which consisted of 70--71% 3H-noradrenaline and 18% 3H-3,4-dihydroxyphenylglycol. Exposure to cocaine or pargyline diminished the formation of 3H-3,4-dihydroxyphenylglycol, suggesting that the glycol is formed presynaptically after neuronal reuptake of the transmitter released by the venom. Our data suggest that the venom depolarizes the noradrenergic neurones of rat hypothalamus, and that the depolarization leads to calcium-dependent release of 3H-noradrenaline.