1. The properties of isolated 150-μm mesenteric resistance vessels from chemically denervated 5-month spontaneously hypertensive and normotensive Wistar—Kyoto rats have been examined.
2. Chemical denervation reduced the blood pressure of both strains of rats, but the denervated spontaneously hypertensive rats were still hypertensive with respect to their denervated Wistar—Kyoto controls.
3. Chemical denervation did not affect the morphological characteristics or calcium sensitivity of the resistance vessels.
4. The results suggest that the media hypertrophy and increased calcium sensitivity seen in resistance vessels from non-denervated spontaneously hypertensive rats are intrinsic defects unrelated to either blood pressure or neurogenic influences.