PEPTIDE RECEPTORS ON ASTROCYTES

In recent years, it has become apparent that astrocytes (at least in v itro) harbor functional receptors to almost all possible neurotransmit ters (with the potential noticeable exception of acetylcholine nicotin ic receptors). Peptides are no exception, since receptors to all neuro peptides known to be produced in the CNS have been found on cultured a strocytes, and the presence of many of these has been confirmed on ast rocytes in vivo. A variety of methodologies have been used to detect p eptide receptors on astrocytes, as summarized in the current review. S pecial emphasis is also put on the possible roles that peptides may pl ay in the regulation of astrocyte functions. These include proliferati on, morphology, release of eicosanoids and arachidonic acid, induction of calcium transients and calcium waves, and control of internal pH, glucose uptake, glycogen metabolism, and gap junctional conductance. R ecent data concerning the effects of natriuretic peptides on astrocyte s are reviewed, and why these peptides may constitute priviledged tool s to test the effects of peptides on astrocyte-neuron interactions is also discussed. (C) 1998 Academic Press.