Molecular aspects of the actions of cyclic nucleotides at synapses.
The neurotransmitters noradrenaline, dopamine, serotonin and histamine, and the neuromodulator adenosine, activate adenylate cyclase via postsynaptic receptors. Acetylcholine and some cholinergic agonists by contrast activate guanylate cyclase via muscarinic receptors. The cyclic nucleotides are believed to modify function in the postsynaptic cell by promoting the phosphorylation of key proteins; in this respect the role of cyclic AMP is far more complex than that of cyclic GMP. In this paper evidence for these postsynaptic actions of the cyclic nucleotides is assessed from studies using cell-containing preparations (slices, etc.) from mammalian brain and sympathetic ganglia, and from cell-free preparations of synaptic plasma membranes. Despite the accumulation of extensive data the precise functional roles of cyclic nucleotides in synaptic transmission remain speculative.
Rodnight
R
R
Department of Biochemistry, Institute of Psychiatry, De Crespigny Park, London, SE5 8AF, U.K.