Comparison of response characteristics of cutaneous mechanoreceptors in normal and neuropathic Sprague-Dawley and spontaneously hypertensive rats.
The activity of single myelinated afferents was recorded from dorsal roots L4-5 in normal Spontaneously Hypertensive rats (SHR) and animals that developed mechanical hypersensitivity following ischemic injury to the sciatic nerve. Control and neuropathic SHRs had significantly higher paw withdrawal threshold to mechanical stimulation than control and neuropathic Sprague-Dawleys (SD). In the SHR rats the mechanical response properties of afferents conducting through the injury site were similar to normals and many of the afferents not conducting through the injury site had spontaneous activity. The only significant difference between the two strains was a faster conduction velocity in afferents recorded from SHR than SD rats. Thus, the behavioral hyposensitivity and less development of mechanical allodynia of SHR rats, compared to SD is not due to differences in the properties of myelinated afferents, but probably involves differences in central inhibitory mechanisms in the two strains.
Bulka
Aleksandra
A
Department of Medical Laboratory Sciences and Technology, Karolinska Institute, S-141 86 Stockholm, Sweden.
Wiesenfeld-Hallin
Zsuzsanna
Z
D000818:Animals; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008465:Mechanoreceptors / Q000502:physiology*; D051381:Rats; D011918:Rats, Inbred SHR; D017207:Rats, Sprague-Dawley; D020426:Sciatic Neuropathy / Q000473:pathology / Q000503:physiopathology*; D012684:Sensory Thresholds / Q000502:physiology*; D012867:Skin / Q000294:innervation*