The importance of the motor nerve for the development of chemosensitivity at the neuromuscular junction
- 12 Downloads
Experiments were performed on kittens to study the role of innervation on the development of the pharmacological responses of the neuromuscular junction. The importance of the nerve for the development of the differing properties of fast and slow muscles was also studied.
It was confirmed that the different responses to depolarising drugs of the slow soleus and fast flexor hallucis longus muscles are not apparent during the first week of the animal's life.
Even when the motor nerves to these muscles were crossed at this time the alien innervation did not affect the subsequent development of the different responses of fast and slow muscles to suxa- and decamethonium. This suggests that the different properties of the postsynaptic membrane are established very early in the animal's life and that they cannot be changed by altering the innervation.
The neuromuscular junctions of these young animals are very insensitive to suxa- and decamethonium. When innervation is delayed, during the early postnatal period, the development of the high sensitivity of the neuromuscular junctions to the blocking and depolarising actions of these drugs was retarded. It is therefore concluded that the motor nerve induces the high chemosensitivity of the adult endplate region.
KeywordsSubsequent Development Neuromuscular Junction Young Animal Motor Nerve Postnatal Period
Unable to display preview. Download preview PDF.
- E. X. Albuquerque andR. J. McIsaac,Early Development of Acetylcholine Receptors on Fast and Slow Mammalian Skeletal Muscle, Life Sci.8, 409–416 (1969).Google Scholar
- J. Axelsson andS. Thesleff,A Study of Supersensitivity in Denervated Mammalian Skeletal Muscle, J. Physiol.147, 178–193 (1959).Google Scholar
- Brenda, Bigland, Beryl, Goetzee, Jennifer, MacLagan andEleanor, Zaimis,The Effect of Lowered Muscle Temperature on the Action of Neuromuscular Blocking Drugs, J. Physiol.141, 425–434 (1958).Google Scholar
- G. L. Brown,The Actions of Acetylcholine on Denervated Mammalian and Frog Muscles, J. Physiol.89, 438–461 (1937).Google Scholar
- B. D. Burns andW. D. M. Paton,Depolarisation of the Motor Endplate by Decamethonium and Acetylcholine, J. Physiol.115, 41–73 (1951).Google Scholar
- J. Diamond andR. Miledi,A Study of Foetal and Newborn Rat Muscle Fibres, J. Physiol.162, 393–408 (1962).Google Scholar
- A. G. Ginetzinsky andN. M. Shamarina,The Tonomotor Phenomenon in Denervated Muscle, Uspekhi Sovremenoj Biologii15, 283–294 (1942).Google Scholar
- P. A. Jewell andE. Zaimis,A Differentiation between Red and White Muscle in the Cat Based on Responses to Neuromuscular Blocking Agents, J. Physiol.124, 417–428 (1954).Google Scholar
- B. Katz andR. Miledi,The Localised Action of ‘End-Plate Drugs’ in the Twitch Fibres of the Frog, J. Physiol.155, 399–415 (1961).Google Scholar
- Jennifer MacLagan andGerta Vrbová,A Study of the Increased Sensitivity of Denervated and Re-Innervated Muscle to Depolarising Drugs, J. Physiol.182, 131–143 (1966a).Google Scholar
- J. MacLagan andG. Vrbová,The Importance of Peripheral Changes in Determining the Sensitivity of Striated Muscle to Depolarising Drugs, J. Physiol.184, 618–630 (1966b).Google Scholar
- R. Miledi,Junctional and Extra-Junctional Acetylcholine Receptors in Skeletal Muscle Fibres, J. Physiol.151, 24–30 (1960a).Google Scholar
- R. Miledi,Properties of Regenerating Neuromuscular Synapses in the Frog, J. Physiol.154, 190–205 (1960b).Google Scholar
- W. L. Nastuk,Membrane Potential Changes at a Single Muscle Endplate Produced by Transitory Application of Acetylcholine with an Electrically Controlled Microjet, Fedn Proc.12, 102 (1953).Google Scholar
- W. D. N. Paton andE. Zaimis,The Methonium Compounds, Pharmac. Rev.4, 219–253 (1952).Google Scholar