Hypothalamic descending afferents to cells of origin of the greater petrosal nerve in the rat, as revealed by a combination of retrograde HRP and anterograde autoradiographic techniques

Abstract

Projections from the hypothalamus to cells of origin of the greater petrosal nerve were studied by the HRP and autoradiographic techniques in the rat. After an injection of [ 3H]amino acids into the hypothalamus and an application of HRP to the greater petrosal nerve, we found that a compact group of HRP-labeled neurons was located within a dense accumulation of silver grains in the nucleus reticularis parvocellularis. The present results show that the hypothalamus projects directly to cells of origin of the greater petrosal nerve.