Group III muscle afferents evoke reflex depressor responses to repetitive muscle contractions in rabbits

J. M. Legramante, G. Raimondi, C. M. Adreani, S. Sacco, F. Iellamo, G. Peruzzi, Marc P Kaufman

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Repetitive twitch contraction of the hindlimb muscles in anesthetized rabbits consistently evokes a reflex depressor response, whereas this type of contraction in anesthetized cats evokes a reflex pressor response in about one-half of the preparations tested. Rapidly conducting group III fibers appear to comprise the afferent arm of the reflex arc, evoking the depressor response to twitch contraction in rabbits because electrical stimulation of their axons reflexly decreases arterial pressure. In contrast, electrical stimulation of the axons of slowly conducting group III and group IV afferents reflexly increases arterial pressure in rabbits. In the present study, we examined the discharge properties of group III and IV muscle afferents and found that the former (i.e., 13 of 20), but not the latter (i.e., 0 of 10), were stimulated by 5 min of repetitive-twitch contraction (1 Hz) of the rabbit triceps surae muscles. Moreover, most of the group III afferents responding to contraction appeared to be mechanically sensitive, discharging in synchrony with the muscle twitch. On average, rapidly conducting group III afferents responded for the 5-min duration of 1-Hz repetitive-twitch contraction, whereas slowly conducting group III afferents responded only for the first 2 min of contraction. We conclude that rapidly conducting group III afferents, which are mechanically sensitive, are primarily responsible for evoking the reflex depressor response to repetitive-twitch contractions in anesthetized rabbits.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume278
Issue number3 47-3
StatePublished - Mar 2000

Fingerprint

Muscle Contraction
Reflex
Rabbits
Muscles
Electric Stimulation
Axons
Arterial Pressure
Hindlimb
Cats

Keywords

  • Arterial blood pressure
  • Autonomic nervous system
  • Breathing
  • Dynamic exercise
  • Sensory nerves
  • Somatic afferents

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

Cite this

Group III muscle afferents evoke reflex depressor responses to repetitive muscle contractions in rabbits. / Legramante, J. M.; Raimondi, G.; Adreani, C. M.; Sacco, S.; Iellamo, F.; Peruzzi, G.; Kaufman, Marc P.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 278, No. 3 47-3, 03.2000.

Research output: Contribution to journalArticle

Legramante, J. M. ; Raimondi, G. ; Adreani, C. M. ; Sacco, S. ; Iellamo, F. ; Peruzzi, G. ; Kaufman, Marc P. / Group III muscle afferents evoke reflex depressor responses to repetitive muscle contractions in rabbits. In: American Journal of Physiology - Heart and Circulatory Physiology. 2000 ; Vol. 278, No. 3 47-3.
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