Colocalization of ATP and nicotinic ACh receptors in the identified vagal preganglionic neurone of rat.

Abstract

1. Effects of exogenous adenosine 5'-triphosphate (ATP) and acetylcholine (ACh) were investigated on acutely dissociated preganglionic neurones in the dorsal motor nucleus of vagus (DMV) of rats using whole-cell patch clamp recording methods. 2. The DMV neurones identified by retrograde transport of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI) fixed onto the cervical vagal nerve bundle were large in size (25-35 jsm diameter) and bipolar or tripolar in shape.3. About 90% of DiI labelled DMV neurones responded to both ATP (10-4 M) and ACh (10-4 M) with inward currents at a holding potential (Vh) of -40 mV.4. The ATP-induced current (IATP) and the ACh-induced current (VACh) reversed their polarities at membrane potentials between +5 and +15 mV, indicating that ATP and ACh increase the membrane permeability to cations. 6. Currents produced by ACh were due to activation of nicotinic receptors because they were mimicked by nicotine and carbachol, and blocked by hexamethonium. In addition, muscarine evoked no response. 7. Only 25 % of nucleus tractus solitarii (NTS) neurones and no hypoglossal neurones responded to the exogenous application of ATP. 8. These results suggest that vagal preganglionic neurones colocalize functionally nicotinic and P2X purinergic receptors.

Action Potential-Independent Release of Glutamate by Ca2+Entry through Presynaptic P2X Receptors Elicits Postsynaptic Firing in the Brainstem Autonomic Network

“…As yet, however, there are few brain regions in which the function of ATP-mediated signaling has been analyzed from the molecular to the whole animal levels. P2X receptors are abundantly located in the cNTS (Collo et al, 1996;Vulchanova et al, 1997;Kanjhan et al, 1999;Yao et al, 2001) and are functional when dissociated (Nabekura et al, 1995). Activation of P2X receptors increases spontaneous EPSC frequency in cNTS slices (Kato and Shigetomi, 2001).…”

Distribution of the P2X2 receptor subunit of the ATP-gated ion channels in the rat central nervous system

“…These CNS regions include: prepiriform cortex (Weisman et al, 1996), hippocampus (Inoue et al, 1995(Inoue et al, , 1996, medial habenula (Edwards et al, 1992), supraoptic nucleus (Day et al, 1993;Hiruma and Bourque, 1995), locus coeruleus Fröhlich et al, 1996), mesencephalic trigeminal nucleus (Cook et al, 1997;Khakh et al, 1997), medial vestibular nucleus , rostral ventrolateral medulla (Sun et al, 1992), nucleus tractus solitarius (Ergene et al, 1994), dorsal motor nucleus of vagus (Nabekura et al, 1995), hypoglossal nucleus (Funk et al, 1997), and spinal cord (Driessen et al, 1994;Salter and Hicks, 1994;Bardoni et al, 1997).…”

Extracellular ATP or ADP Induce Chemotaxis of Cultured Microglia through Gi/o-Coupled P2Y Receptors

“…The roles of extracellular ATP as a neurotransmitter and neuromodulator in the CNS have been well documented. For example, ATP induces excitation and increases in calcium in various neurons in the brain (Edwards et al, 1992;Shen and North, 1993;Chen et al, 1994;Inoue et al, 1995;Nabekura et al, 1995). In addition to the role played by ATP in neurons, effects of ATP on glial cells have also been demonstrated.…”