Responses of isolated Golgi tendon organs of the cat.

Abstract

SUMMARY1. The responses to stretch have been studied in living, isolated Golgi tendon organs (GTOs) from tail muscles of cat. Experiments were performed in vitro and consisted of subjecting single GTOs to controlled ramp-and-hold stretch while recording the response from their sensory axons raised in oil.2. The threshold force required for sustained afferent discharge was measured directly, and found to be between 8 and 170 dynes at 240 C for nine GTOs tested. Beyond threshold, the discharge frequency is approximately proportional to applied static tension over a wide range. Sensitivity to tension varies among different GTOs and appears to be inversely correlated with mechanical stiffness.3. With impulse activity blocked by tetrodotoxin, graded receptor potentials could be recorded whose amplitude varied in proportion to applied static tension. All GTOs examined showed in addition a dynamic response, which became larger with increasing velocity of ramp stretch. This dynamic sensitivity appears in the receptor potential and is then augmented by an apparent accommodative process at the impulse initiating site.4. Based on the above findings, possible mechanical models are discussed for the sensory transduction mechanism.

Interaction of impulse activities originating from individual Golgi tendon organs innervated by branches of a single axon.

“…Fig. 5 shows a record taken from experiments designed to record receptor potentials from the nerve of an isolated Golgi tendon organ in vitro (Fukami & Wilkinson, 1977). A ramp-and-hold stretch (middle trace) of 10 jsm amplitude produced a single action potential (top trace) followed by afterhyperpolarization lasting about 100 msec (top and bottom traces).…”

“…Quite evident from these graphs is that the reduced excitability curves obtained from a pair are rather distinct from each other. The great variability of sensitivity to stretch among individual tendon organs (Fukami & Wilkinson, 1977) Gregory, Harvey & Proske (1977) for secondary endings of muscle spindles as well as tendon organs in cat soleus muscles and in lizards. The attempt was without success except in one case where the reduced excitability was followed by a slight increase (-5 %) in excitability lasting for about 60 msec.…”

“…injection) the tail was skinned. Immediately after being detached at its base from the rest of the body the tail was transferred to a bath containing modified Locke solution (Hunt & Ottoson, 1975;Fukami & Wilkinson, 1977). The thin muscles located in the dorsolateral aspect of the tail were exposed to the solution as quickly as possible by retracting their tendons laterally.…”

“…It has recently been shown that a living single Golgi tendon organ, with or without muscle fibres attached, can be isolated from cat tail muscles (Fukami & Wilkinson, 1977). The isolated preparation may be kept in a good functional state for many hours in vitro.…”

O treino da flexibilidade muscular e o aumento da amplitude de movimento: uma revisão crítica da literatura

“…À medida que a temperatura do músculo aumenta, a quantidade de força requerida para alongar os tecidos contrácteis e não contrácteis e o tempo durante o qual a força de alongamento precisa de ser aplicada diminuem. Com o aumento da temperatura intramuscular, o tecido conectivo cede mais facilmente ao alongamento e a sensibilidade dos órgãos tendinosos de Golgi aumenta (o que leva a uma maior inibição muscular) 59 . Para além disso, o aquecimento também minimiza a probabilidade de microtraumas aos tecidos moles durante o alongamento e, desse modo, pode diminuir a dor muscular tardia que ocorre após os exercícios 60,61,62,63 .…”