“…Nevertheless, the morphology of glial cells from adult cockroaches (Howes et al, 1989), pupal honeybees (Gascuel and Masson, 1991), and locust embryos ( Vanhems and Delbos, 1987) has been studied in vitro and a number of functional studies revealed that insect glial cells express high affinity transporters for L-glutamate, GABA, and histamine (Campos-Ortega, 1974;Borycz et al, 2002;Soustelle et al, 2002, Freeman et al, 2003, respond to neuronal transmitters (Giles and Usherwood, 1985;Leitch et al, 1993;Schofield and Treherne, 1985) and may require neuron-derived trophic signals for survival and differentiation (Bergmann et al, 2002;Hidalgo et al, 2001;Sen et al, 2004). A prerequisite for in vitro studies on primary cell cultures from insect nervous systems is the reliable distinction of glial and neuronal cell bodies, which is especially problematic in fresh cell cultures, where both cell types assume spherical shapes and lack characteristic processes (Beadle et al, 1982(Beadle et al, , 1987. A simple and widely used method to identify glial cells in histological studies is based on the absence of antihorseradish peroxidase (HRP) immunoreactivity, which labels the pan-neuronally expressed surface protein Nervana (Jan and Jan, 1982;Sun and Salvaterra, 1995a,b) and this method has recently been adopted to identify cultured glia cells (Loesel et al, 2006).…”