Coexistence of acetylcholinesterase-, human growth hormone-releasing factor(1–37)-, α-melanotropin- and melanin-concentrating hormone-like immunoreactivities in neurons of the rat hypothalamus: a light and electron microscope study

Using an antiserum (AS) raised against rat cerebral acetylcholinesterase (AChE), we revealed a neuron population in lateral and dorsal areas of the posterior rat hypothalamus. These neurons were previously described using antibodies to human growth hormone-releasing factor(1–37) (GRF-37), α-melanotropin (α-MSH) and melanin-concentrating hormone (MCH). Different intracytoplasmic distributions of the immunodeposits were observed depending on the used serum. Ultrastructural investigations demonstrated that AChE-AS labeled rough endoplasmic reticulum and nuclear envelope in control rats. MCH-AS stained Golgi apparatus in control animals and secretory granules in colchicine-injected rats. GRF-37-AS always revealed secretory granules, and α-MSH-AS gave the same staining only after colchicine injection.