From the Golgi–Cajal mapping to the transmitter-based characterization of the neuronal networks leading to two modes of brain communication: Wiring and volume transmission

Abstract

After Golgi-Cajal mapped neural circuits, the discovery and mapping of the central monoamine neurons opened up for a new understanding of interneuronal communication by indicating that another form of communication exists. For instance, it was found that dopamine may be released as a prolactin inhibitory factor from the median eminence, indicating an alternative mode of dopamine communication in the brain. Subsequently, the analysis of the locus coeruleus noradrenaline neurons demonstrated a novel type of lower brainstem neuron that monosynaptically and globally innervated the entire CNS.Furthermore, the ascending raphe serotonin neuron systems were found to globally innervate the forebrain with few synapses, and where deficits in serotonergic function appeared to play a major role in depression. We propose that serotonin reuptake This will lead to the unified execution of information handling and trophism for optimal brain function and survival.

The Existence of FGFR1–5-HT1A Receptor Heterocomplexes in Midbrain 5-HT Neurons of the Rat: Relevance for Neuroplasticity

“…We show for the first time the existence of FGFR1-5-HT1A receptor heterocomplexes in 5-HT nerve cells of the dorsal and median raphe nuclei of the midbrain by means of the PLA technique as has previously been postulated (Fuxe et al, 2007). These 5-HT neurons are known from previous work to express FGFR1 and to contain high amounts of 5-HT1A immunoreactivity and a high density of 5-HT1A binding sites (Pazos and Palacios, 1985;Albert et al, 1996;Artigas et al, 1996;Belluardo et al, 1997).The PLA-positive clusters have a location in the cytoplasm and are also associated with the plasma membrane.…”

“…In line with this hypothesis, extended treatment with the SSRI zimelidine causes increases in 5-HT immunofluorescence in the dorsal raphe (Fuxe et al, 1983). The receptors for epidermal growth factor, plateletderived growth factor, insulin-like growth factor-1, FGFs, and neurotrophins can, in fact, be transactivated in response to GPCR activation even in the absence of neurotrophic factor binding at the cell surface via direct (heteromeric receptor complexes) and/or indirect GPCR/RTK receptor interactions (Luttrell et al, 1999;Lee and Chao, 2001;Kotecha et al, 2002;Lee et al, 2002;Ferguson, 2003;Rajagopal et al, 2004;Shah and Catt, 2004;Berghuis et al, 2005;Fuxe et al, 2007). Evidence is here presented for the existence of FGFR1-5-HT1A receptor heterocomplexes in the mesencephalic raphe 5-HT nerve cells.…”

The role of transmitter diffusion and flow versus extracellular vesicles in volume transmission in the brain neural–glial networks

“…Recently, surface diffusion of astrocytic glutamate transporters were found to shape the kinetics of excitatory postsynaptic currents and thus synaptic transmission [32]. VT mediated by monoamines seems to depend on extrasynaptic release and transmitter spread to extrasynaptic receptors [11,14,15,18,33] since inter alia a large proportion of monoamine terminals lack postjunctional complexes [34,35]. Rice & Cragg [36] have modelled DA extrasynaptic transmission from terminals based on DA spillover after quantal release, considering a large number of experimental data from their own and other groups.…”

Extracellular-vesicle type of volume transmission and tunnelling-nanotube type of wiring transmission add a new dimension to brain neuro-glial networks

“…Two major complementary modes of intercellular communication exist in the central nervous system (CNS), namely wiring transmission (WT) and volume transmission (VT) [1][2][3][4][5][6][7][8][9][10][11]. WT is a point-to-point communication in the CNS(GPCRs) [20] highly suited to integrate the signals of synaptic transmission and VT at the plasma membrane level.…”