Multisynaptic neuronal pathways from the submandibular and sublingual glands to the lamina terminalis in the rat: A model for the role of the lamina terminalis in the control of osmo- and thermoregulatory behaviour

1. The putative regulatory role of the lamina terminalis in the central control of salivation was investigated in the rat using the viral-tracing technique and Fos-immunohistochemistry. 2. Neurons situated in the lamina terminalis, such as the vascular organ of the lamina terminalis (OVLT), median preoptic nucleus (MnPO) and subfornical organ (SFO), were retrogradely labelled after pseudorabies virus injections into the submandibular or sublingual gland. 3. Viral tracing combined with glandular denervation showed that lamina terminalis structures sent efferents, in particular, to the parasympathetic side of submandibular gland innervation. 4. Saliva lost under heat stress has severe implications for the body fluid economy of rats and a key to the understanding of the central regulation of heat-induced salivation may be the integrative role of the lamina terminalis processing thermoregulatory and osmoregulatory information.