Immunohistochemical localization of guanylate cyclase within neurons of rat brain.

Abstract

The immunohistochemical localization of guanylate cyclase [GTP pyrophosphate-lyase (cyclizing), EC 4.6.1.2] has been examined in rat neocortex, caudate-putamen, and cerebellum by using specific monoclonal antibodies. Immunofluorescence could be seen within somata and proximal dendrites of neurons in these regions. A nuclear immunofluorescence reaction to guanylate cyclase was characteristically absent. Guanylate cyclase [GTP pyrophosphate lyase (cyclizing), EC 4.6.1.2] catalyzes the formation of guanosine 3',5'-monophosphate (cyclic GMP) from GTP. Two forms of the enzyme, one soluble and the other membrane-associated, have been described in most tissues studied (1). Characterization of the enzyme in murine brain (2) demonstrates comparable enzyme activity in the neocortex and cerebellum and highest total guanylate cyclase activity in the caudate-putamen complex. Subcellular fractionation ofmouse (2) and rat (3) caudate-putamen homogenates shows the specific activity of the soluble form of the enzyme to be greater than that of the particulate fraction. It has been hypothesized that cyclic GMP has an important role in the mediation of cholinergic-muscarinic receptor actions (4-7), glutamate neurotransmission (8), and the generation of seizure activity (9) in the nervous system.Another experimental approach, immunohistochemical localization of cyclic GMP in various brain regions, has demonstrated accumulation of this cyclic nucleotide in neuroglia (10, 11), in stellate and basket neurons of the cerebellum (10), in postganglionic neurons of the superior cervical ganglion (12, 13), and predominantly within neurons ofthe caudate-putamen and the neocortex (14). Immunocytochemistry in the latter regions demonstrated cyclic GMP accumulation at the subsynaptic terminal density and adjacent cytoplasm in type 1 synapses (14). Cyclic GMP has been proposed to exert its physiological actions through phosphorylation of a cyclic GMP-dependent protein kinase (15). Cyclic GMP-dependent protein kinase activity is extremely elevated in the cerebellum (16), and immunohistochemical localization of this enzyme has been demonstrated within Purkinje cells and their processes (17). Cyclic GMP phosphodiesterase (EC 3.1.4.17), the enzyme that hydrolyzes cyclic GMP to 5'-GMP, has been detected cytochemically at the subsynaptic density of axospinous synapses of the rat caudate-putamen complex and neocortex (18). A preferential localization of soluble guanylate cyclase in neurons has been described in disrupted rat brain (19) and after kainic acid production of lesions of the rat caudate-putamen (3).The present work describes the immunohistochemical localization of guanylate cyclase in three central nervous system areas by using four different monoclonal antibodies directed against the soluble form of rat lung enzyme. The antibodies crossreact avidly with soluble guanylate cyclase from all rat tissues examined, including brain, and may partially interact with the particulate enzyme form (20). Specific localization of guanylate cycla...

Immunohistochemical Localization of cGMP-binding cGMP-specific Phosphodiesterase (PDE5) in Rat Tissues

“…Neuronal NO synthase is found in parallel fibers but not in Purkinje cells and climbing fibers (Rodrigo et al 1994). In contrast, expression of soluble guanylate cyclase is restricted to Purkinje cells (Ariano et al 1982). NO released from parallel fibers evokes cGMP generation in Purkinje cells by soluble guanylate cyclase.…”

Presynaptic N -methyl- d -aspartate receptors at the parallel fiber–Purkinje cell synapse

“…A postsynaptic expression of the phenomenon thus appeared more likely, but required a trans-synaptic messenger. In the search for such a messenger, we took into account reports of the presence of NO synthase (NOS) in PFs (24), of NO production by these fibers (25), and of a body of observations suggesting that NO released by the PFs can activate the soluble guanylate cyclase (sGC) expressed by the PCs (26,27) and trigger a postsynaptic decrease in the glutamate sensitivity of ␣-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. This trans-synaptic signaling pathway has been most systematically described in the analysis of cerebellar long-term depression (ref.…”

Nitric oxide-mediated cGMP synthesis in oligodendrocytes in the developing rat brain

“…Early biochemical studies (see Ferrendelli, 1978, for a review of the older literature), immunocytochemical studies (Ariano et al, 1982;Chann-Palay and Palay, 1979;Nakane et al, 1983), and mRNA in situ hybridization studies (Burgunder and Cheung, 1994;Giulli et al, 1994;Matsuoka et al, 1992) all show a wide spread occurrence of sGNC in the CNS. In addition, immunocytochemical studies on NO-mediated cGMP production demonstrated structures capable of synthesizing cGMP in almost all parts of the central and peripheral nervous system (De Vente and Steinbusch, 1992;Hopkins et al, 1996;Shuttleworth et al, 1993;Smet et al, 1996;Southam and Garthwaite, 1993;Young et al, 1993).…”