title: Peripheral neural mechanism of hypertension in rat models--peripheral sympathetic neurotransmission in hypertension.
abstract: To investigate the peripheral neural mechanism of hypertension, norepinephrine release from sympathetic nerve endings was evaluated in various hypertensive rat models. The isolated mesenteric vasculatures were prepared in 7-9-week-old and 20-22-week-old spontaneously hypertensive rats (SHR), DOCA-salt hypertensive rats (DOCA-HT), two-kidney, one clip renal hypertensive rats (2K1C-HT) and their age-matched normotensive controls. The vasoconstrictor responses to exogenous norepinephrine (EN) were significantly enhanced in all hypertensive rat models compared with their age-matched normotensive controls. The pressor responses to electrical nerve stimulation (NS) were greater in SHR than age-matched Wistar-Kyoto (WKY) rats, and were also increased in DOCA-HT. The norepinephrine overflow during NS was significantly greater in young SHR and chronic DOCA-HT than in the normotensive controls. In 2K1C-HT, the norepinephrine overflow by NS was somewhat reduced compared with sham-operated normotensive controls. Inhibition by calcium-antagonist (verapamil) of the pressor responses and norepinephrine overflow during NS was significantly greater in young SHR and chronic DOCA-HT than in their controls. The facilitatory effect on the norepinephrine overflow exerted by the alpha 2-adrenoceptor antagonist, yohimbine, during NS was significantly less in young SHR and chronic DOCA-HT.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D006973:Hypertension / Q000235:genetics / Q000503:physiopathology*; D007473:Ion Channels / Q000502:physiology; D008297:Male; D009411:Nerve Endings / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D010525:Peripheral Nerves / Q000503:physiopathology*; D051381:Rats; D011919:Rats, Inbred Strains / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000502:physiology; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D009435:Synaptic Transmission
chemical_list: D007473:Ion Channels; D011942:Receptors, Adrenergic, alpha; D002118:Calcium; D009638:Norepinephrine