Compounds of general formula (I): R1-Wn-Xm-AA1-AA2-AA3-AA4-AA5-AA6-AA7-AA8-AA9-Yp-Zq-R2 (I)their stereoisomers, mixtures thereof and/or their cosmetically or pharmaceutically acceptable salts, preparation processes, cosmetic or pharmaceutical compositions which contain them and their use in medicine, particularly in the treatment and/or prevention of pain, inflammation, itching, neurological, compulsive and/or neuropsychiatric diseases and/or disorders and in processes of treatment and/or care of the skin, hair and/or mucous membranes mediated by neuronal exocytosis.