Abstract
Intracisternal injection of L-proline in concious rat increased blood pressure through peripheral vasopressin release (Jpn J Physiol 1995), and microinjection of L-proline into the caudal ventral medulla of anesthetized rat decreased blood pressure through vascular sympathetic suppression (Annual Meeting 2002 in Hiroshima). These neural effects of L-proline suggest existence of proline sensitive receptors in the rat brain. However, there are no data for precise localization of L-proline within the brain. In the present study, we raised antibody against L-proline in the rabbit and purified by an affinity chromatography the antibody which specifically recognized L-proline. Immunohistochemical staining of the rat brain slices using the antibody detected positively stained neurons in the hypothalamus and brainstem indicating that endogenous L-proline is localized in a group of neurons in the rat brain. Our observation supports roles of proline as a neurotransmitter candidate. [Jpn J Physiol 54 Suppl:S212 (2004)]
