The neurotropic effect of pituitary somatotropin and a fragment of it

Recently it was established in experiments in vitro that somatotropic hormone (STH) and its fragment 77-107, which possesses the growth-stimulating activity characteristic of STH, are capable of increasing the activity of phosphodiesterase, which catalyzes the decomposition of cyclic 3',5'-adenosine monophosphate (cAMP), in synaptosomes and glial cells isolated from the rat cerebral cortex. In this work the authors studied the influence of STH and its fragment 77-107 under conditions of their microiontophoretic delivery on the electrical activity of single neurons of various regions of the rat brain and on the sensitivity of these neurons to the classic neurotransmitter norepinephrine (NE).