Age-related reduction of reflex bradycardia in conscious rats by catecholaminergic nucleus tractus solitarius lesions

https://doi.org/10.1016/0047-6374(93)90111-4Get rights and content

Abstract

To determine whether catecholaminergic lesions in the nucleus tractus solitarius (NTS) have age-related baroreflex effects, we compared conscious 3-month- and 14-month-old rats pretreated with either 6-hydroxydopamine (6-OHDA) or vehicle injected into the NTS. Body weights fell immediately in both age groups, but after 2 weeks the weight loss persisted only in 14-month-old rats. Mean pressures and heart rates, though diminished after 3 days, were later elevated slightly in 3-month- but not in 14-month-old rats. Two weeks after 6-OHDA pretreatment, reflex tachycardia was reduced in both age groups, but reflex bradycardia was reduced only in 3-month-old and not in 14-month-old rats. Corresponding changes in vehicle-treated rats were not significant. Because 6-OHDA induced lesions in the NTS inhibited reflex bradycardia selectively at 3 but not at 14 months of age, our results suggest that catecholaminergic mechanisms in the NTS for regulating reflex bradycardia become impaired with age.

References (28)

  • K.Y. Koda et al.

    Distribution of catecholamine-containing cell bodies and blood vessels in the rat nucleus tractus solitarius

    Brain Res.

    (1983)
  • J.P. Chalmers

    Brain amines and models of experimental hypertension

    Circ. Res.

    (1975)
  • W. de Jong et al.

    Chemical stimulation of the nucleus of the solitary tract and the resulting blood pressure response

    J. Cardiovasc. Pharmacol.

    (1982)
  • D.W. Snyder et al.

    Chronic lability of arterial pressure produced by selective destruction of the catecholamine innervation of the nucleus tractus solitarii in the rat

    Circ. Res.

    (1978)
  • Cited by (0)

    View full text