The effect of atherosclerosis on neuromodulation of sympathetic neurotransmission by neuropeptide Y and calcitonin gene-related peptide in the rabbit mesenteric artery.
The neuromodulatory actions of neuropeptide Y (NPY) (0.1 microM) and calcitonin gene-related peptide (CGRP) (0.01 microM) on nerve-evoked contractions have been studied in the Watanabe heritable hyperlipidemic (WHHL) rabbit mesenteric artery from 4-, 6- and 12-month-old animals with New Zealand white (NZW) rabbits being used as age- and sex-matched controls. Nerve-evoked contractions in 12-month-old rabbits were smaller in WHHL in comparison to NZW rabbits, with no difference between the two strains of rabbit at 4 and 6 months of age. Both the potentiating effect of NPY and the inhibitory effect of CGRP on nerve-evoked contractions increased significantly at 12 months of age compared with responses measured in younger WHHL rabbits, and were greater than in 12-month-old control NZW rabbits. In contrast, the direct smooth muscle relaxant response of CGRP on raised-tone preparations was not different between the two strains of rabbit at any age. Both NPY-immunoreactive and CGRP-immunoreactive nerve fibres were less varicose in 6- and 12-month-old WHHL rabbits when compared with younger WHHL rabbits and NZW controls. In conclusion, this study shows that while nerve-evoked contractions are reduced, in the 12-month-old WHHL rabbit mesenteric artery, the neuromodulatory actions of NPY and CGRP are augmented.
Stewart-Lee
A L
AL
Department of Anatomy and Developmental Biology, University College London, UK.
Aberdeen
J
J
Burnstock
G
G
D000367:Age Factors; D000818:Animals; D001161:Arteriosclerosis / Q000378:metabolism / Q000503:physiopathology*; D015740:Calcitonin Gene-Related Peptide / Q000032:analysis / Q000494:pharmacology*; D005260:Female; D008638:Mesenteric Arteries / Q000187:drug effects / Q000294:innervation*; D008856:Microscopy, Fluorescence; D009412:Nerve Fibers / Q000737:chemistry; D009478:Neuropeptide Y / Q000032:analysis / Q000494:pharmacology*; D011817:Rabbits; D013564:Sympathetic Nervous System / Q000098:blood supply / Q000187:drug effects* / Q000502:physiology; D009435:Synaptic Transmission / Q000187:drug effects* / Q000502:physiology
D009478:Neuropeptide Y; D015740:Calcitonin Gene-Related Peptide