title: Ultrastructural localisation of ATP-gated P2X2 receptor immunoreactivity in the rat hypothalamo-neurohypophysial system.
abstract: The distribution of the P2X(2) subtype of the purine receptor associated with the extracellular signalling activities of ATP was studied in the rat hypothalamo-neurohypophysial system at the electron microscope level. Receptors were labelled with ExtrAvidin-horseradish peroxidase preembedding immunocytochemistry using a polyclonal antibody against a fragment of an intracellular domain of the receptor. Immunoreactivity to P2X(2) receptors was localised in: (i) paraventricular and supraoptic nuclei-in subpopulations of endocrine neurones, neurosecretory and non-neurosecretory axons and dendrites; and (ii) the neurohypophysis-in pituicytes and subpopulation of neurosecretory axons. In both the hypothalamic nuclei examined, labelled asymmetric axo-dendritic synapses were commonly observed. These synapses involved either P2X(2)-labelled axon terminals (synaptic buttons) and unlabelled dendrites or labelled dendrites and unlabelled axon terminals. Axo-somatic synapses established by P2X(2)-positive axons on P2X(2)-positive endocrine cell bodies as well as on P2X(2)-negative somata were also observed. The functional significance of these findings is discussed.
authors.affiliation: Department of Anatomy and Developmental Biology, University College London, Gower Street, London WC1E 6BT, UK.
authors.forename: A
authors.initials: A
authors.lastname: Loesch
authors.forename: S
authors.initials: S
authors.lastname: Miah
authors.forename: G
authors.initials: G
authors.lastname: Burnstock
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D003594:Cytoplasmic Granules / Q000502:physiology / Q000648:ultrastructure; D003712:Dendrites / Q000502:physiology / Q000648:ultrastructure; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology* / Q000648:ultrastructure; D008297:Male; D016253:Microscopy, Immunoelectron; D009474:Neurons / Q000502:physiology* / Q000648:ultrastructure; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology / Q000648:ultrastructure; D010904:Pituitary Gland, Posterior / Q000502:physiology / Q000648:ultrastructure; D051381:Rats; D017207:Rats, Sprague-Dawley; D018048:Receptors, Purinergic P2 / Q000032:analysis / Q000378:metabolism*; D058476:Receptors, Purinergic P2X2; D013495:Supraoptic Nucleus / Q000502:physiology / Q000648:ultrastructure; D013572:Synaptic Vesicles / Q000502:physiology / Q000648:ultrastructure
chemical_list: C546403:P2rx2 protein, rat; D018048:Receptors, Purinergic P2; D058476:Receptors, Purinergic P2X2; D000255:Adenosine Triphosphate