The role of the caudate-putamen nucleus in salivary secretion induced by L-DOPA.

Experiments were performed in rats of the Wistar strain anesthetized with alpha-chloralose (100 mg/kg). Electrolytic lesion of either components of the striopallidal complex (corpus striatum, globus pallidus or entopeduncular nucleus) reduced the sensory response to L-DOPA in the contralateral submaxillary glands. Damage to other neural structures, directly or indirectly related to the striopallidal system, left the salivary response unaffected. These structures were: substantia nigra, cerebral cortex, ventromedial and center median-parafascicular thalamic nuclei, nucleus accumbens and posterior hypothalamic areas, including the medial forebrain bundle and lateral habenular nucleus. However, lesions placed in H1-H2 fields of Forel and reticular formation, lateral to the periaqueductal gray, reduced the salivary response in the contralateral glands. This effect was similar to that observed in animals with lesions of the striopallidal complex. From this study, it is concluded that the striatum is the target area for the central effect of L-DOPA on salivary secretion, by activation of pathways descending through the fields of Forel and mesencephalic reticular formation to the contralateral lower brain stem.