Galantide

Galantide, a non-specific galanin receptor antagonist, is a peptide consisting of fragments of galanin and substance P. Galantide recognizes two classes of galanin binding sites (K_D<0.1 nM and ~6 nM) in the rat hypothalamus. Galantide dose dependently (IC₅₀=1.0 nM) antagonizes the galanin-mediated inhibition of the glucose-induced insulin secretion from mouse pancreatic islets. Galantide appears to bind to a single population of SP receptors (K_D~40 nM)^[1][2][3]. In Vitro: Galantide do not activate the K⁺ conductance but produces a concentration-dependent antagonism (IC₅₀=4 nM) of the galanin-induced increase in K⁺ conductance. Galantide acts like galanin and inhibits the voltage-dependent Ba2+ current (IBa). The inhibition of IBa also is concentration dependent (IC₅₀=16 nM) and the maximum inhibition produced by galantide is approximately 40%^[3]. In Vivo: Intracerebroventricular injection of galanin (5 micrograms/rat) inhibited sexual behavior in experienced male rats--without producing any other locomotor or behavioral deficit-, injection of the galanin antagonist, galantide, by the same route (1 or 2 micrograms/rat) stimulated sexual behavior (improving arousal, motivation and performance indexes) and antagonized the effect of galanin^[2]. Galantide ameliorates mild acute pancreatitis (AP). Galantide significantly reduces AP-induced hyperenzymemia by 41–49%^[3]. Galantide has been found to improve social memory in 'socialrecognition' test when i.c.v. administered at doses varying from 6-6000 nM^[4].