A role for non-neuronal cells in synchronization of intracellular calcium oscillations in primate LHRH neurons

Abstract

A study using multiunit activity recording from the medial basal hypothalamus indicates that pulsatile luteinizing hormone-releasing hormone (LHRH) release is a consequence of synchronized activity of individual LHRH neurons. An increase in single unit spike components extracted from the multiunit “LHRH pulse-generator” activity by cluster analysis occurs as a simultaneous increase in the firing rate of many individual hypothalamic neurons rather than the recruitment of new bursting neurons. The mechanism underlying LHRH synchronization is currently unknown. This is because, unlike oxytocin and vasopressin neurons, LHRH neurons do not form a nucleus in the hypothalamus and there is little evidence for physical contact between LHRH neurons—such as synapses or syncytium formation—that allow the synchronization of LHRH neurons. The perikarya of LHRH neurons are covered by glial sheaths and LHRH neuroterminals are intimately associated with glial end feet. The chapter also explains synchronization of [Ca 2 +] i oscillations and LHRH neurosecretion.