The transmitters of the hypothalamus

Abstract

Monoamines, GABA and acetylcholine are the best-known transmitters of the hypothalamus (Fuxe and Hökfelt, 1969; Fuxe and Jonsson, 1974: Björklund et al., 1973; Carlsson et al., 1962; Dahlström and Fuxe, 1964; Hökfelt et al., 1974b; Ungerstedt, 1971; Roberts, 1975; Roberts et al., 1975; Tappaz et al., 1976; Vogt, 1954; Snyder and Taylor, 1972; Brownstein et al., 1975b; Fuxe et al., 1976b; Hökfelt et al., 1978). Recently evidence has accumulated that hypothalamic hormones such as luteinising hormone releasing hormone (LH-RH), somatostatin, thyrotrophin releasing hormone (TRH) and other types of peptides such as substance P and enkephalin can also subserve a transmitter or a modulator role (changing the action of a transmitter) at synaptic junctions within the hypothalamus (Barry and Dubois, 1974; Brownstein et al., 1975a; Brownstein et al., 1974; Elde et al., 1976a; von Euler and Gaddum, 1931; Fuxe et al., 1976a; Fuxe et al., 1976b; Ganten et al., 1975; Giachetti et al., 1976; Guillemin, 1978; Guillemin et al., 1976; Elde et al., 1976b; Hökfelt et al., 1974a; Hökfelt et al., 1975b; Hökfelt et al., 1975c; Hökfelt et al., 1975e; Reichlin et al., 1976; Renaud et al., 1975; Said and Rosenberg, 1976 Vanderhaeghen et al., 1975; Zimmerman, 1976; Larsson et al., 1976; Fuxe et al., 1977d; Hökfelt et al., 1978). In the present article the distribution of the various monoamine-, GABA-, acetylcholine- and peptide-containing neurones within the hypothalamus will be described. The article will then describe how monoamine systems can control activity in hypothalamic hormone-containing pathways and in other types of peptide-containing pathways. Finally, how the various types of transmitters and/or modulators can influence activity in the catecholamine (CA) systems of the hypothalamus, will be discussed with particular reference to the dopamine (DA) systems in the median eminence.