[Cell death induced by noradrenaline in cultured chick spinal cord neurons]

There is accumulating evidence that some substances which are originally transmitters affect neuronal development. Though noradrenaline (NA) containing neurons in the brain-stem innervate motoneurons as well as interneurons in the spinal cord, little is known about whether or not NA may play roles other than neurotransmission during development. Therefore, we have examined the effects of NA on developing neurons in the spinal cords of chick embryos. The dissociated cells were incubated with chemicals and the number of surviving cells was counted 2 days later. It was found that NA induced cell death in a dose dependent manner (EC50, 13 microM). Phentolamine, an alpha-adrenoceptor antagonist, prevented the cell death induced by NA (KD, 1.5 nM), whereas, alprenolol, a beta-adrenoceptor antagonist, did not. Furthermore, prazosin, an alpha 1-adrenoceptor antagonist, prevented the NA-induced cell death, but yohimbine, an alpha 2-adrenoceptor antagonist, did not. Dithiothreitol, an antioxidant, did not prevent NA-induced cell death. These results indicate that NA induces cell death in the developing neurons in the chick spinal cord through alpha 1-adrenoceptors.