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Titolo:
Specialised sympathetic neuroeffector associations in immature rat iris arterioles
Autore:
Sandow, SL; Hill, CE;
Indirizzi:
Australian Natl Univ, John Curtin Sch Med Res, Div Neurosci, Autonom Synapse Grp, Canberra, ACT 0200, Australia Australian Natl Univ Canberra ACT Australia 0200 rra, ACT 0200, Australia
Titolo Testata:
JOURNAL OF ANATOMY
, volume: 195, anno: 1999,
parte:, 2
pagine: 257 - 270
SICI:
0021-8782(199908)195:<257:SSNAII>2.0.ZU;2-W
Fonte:
ISI
Lingua:
ENG
Soggetto:
GUINEA-PIG; DILATOR MUSCLE; SMOOTH-MUSCLE; NEUROMUSCULAR-TRANSMISSION; IRIDEAL ARTERIOLES; MESENTERIC VEINS; SENSORY NERVES; AXONS; NORADRENALINE; RECEPTORS;
Keywords:
adrenergic neurotransmission; iris; synaptic vesicles; vasculature;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
44
Recensione:
Indirizzi per estratti:
Indirizzo: Sandow, SL Australian Natl Univ, John Curtin Sch Med Res, Div Neurosci, Autonom Synapse Grp, Canberra, ACT 0200, Australia Australian Natl Univ Canberra ACT Australia 0200 00, Australia
Citazione:
S.L. Sandow e C.E. Hill, "Specialised sympathetic neuroeffector associations in immature rat iris arterioles", J ANAT, 195, 1999, pp. 257-270

Abstract

Sympathetic nerve-mediated vasoconstriction in iris arterioles of mature rats occurs via the activation of a,,adrenoceptors alone, while in immature rat iris arterioles, vasoconstriction occurs via activation of both a,and alpha(2)-adrenoceptors. In mature rats the vast majority of sympathetic varicosities form close neuroeffector junctions. Serial section electron microscopy of 14 d iris arterioles has been used to determine whether restrictionin physiological receptor types with age may result from the establishmentof these close neuroeffector junctions. Ninety varicosities which lay within 4 mu m of arteriolar smooth muscle were followed for their entire length. Varicosities rarely contained dense cored vesicles even after treatment with 5-hydroxydopamine. 47 % of varicosities formed close associations with muscle cells and 88 % formed close associations with muscle cells or melanocytes. Varicosities in bundles were as likely as single varicosities to form close associations with vascular smooth muscle cells, although the distribution of synaptic vesicles in single varicosities did not show the asymmetric accumulation towards the smooth muscle cells seen in the varicosities in bundles which were frequently clustered together. We conclude that restriction of physiological receptor types during development does not appear tocorrelate with the establishment of close neuroeffector junctions, although changes in presynaptic structures may contribute to the refinement of postsynaptic responses.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 14/07/20 alle ore 12:27:32