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The sensitization of high threshold mechanoreceptors with myelinated axons by repeated heating.
Author(s) -
Fitzgerald M,
Lynn B
Publication year - 1977
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.1977.sp011730
Subject(s) - sensitization , stimulation , nociceptor , radiant heat , mechanoreceptor , threshold of pain , cold sensitivity , sural nerve , medicine , anesthesia , nociception , chemistry , anatomy , materials science , biochemistry , receptor , mutant , immunology , composite material , gene
1. Seventy high threshold mechanoreceptor units (HTMs) with myelinated axons were isolated from the sural nerves of cats and rabbits. Thirteen cat and forty‐two rabbit HTMs were testec by controlled, repeated heating of the skin of the foot or lower leg to noxious levels. 2. Many of the units (77% in the cat and 40% in the rabbit) fired to heating. Only six (11%) of these fired to the first brief heating to 50‐55 degrees C. The rest required 2‐6 heat trials before responding. 3. Heat responding units always became more sensitive with repeated heat stimulation but their mechanical sensitivity showed no comparable changes when heat sensitization occurred. 4. If these results are applicable to man, they suggest that HTMs play little role in generating the first pain that follows skin heating but that they may be involved in the increased sensitivity to heat pain (hyperalgesia) shown by skin previously injured by heating.