Polyamine treatment in early development leads to increased numbers of rat sympathetic neurons

Sympathetic and sensory neurons were counted in 35-day-old rats which were treated with polyamines from day 2 to day 9 after birth. The treatment led to an increase, averaging about 34%, in the number of sympathetic neurons in the superior cervical ganglion. The number of sensory neurons in the nodose ganglion was not changed. In sympathetic ganglia the activity of the neurotransmitter synthesizing enzyme tyrosine hydroxylase was also increased. The results demonstrate that increased polyamine supply during a limited developmental period can lead to an increased number of sympathetic neurons, possibly through enhanced neuron survival.