| Effect of knee joint stimulation on the activity of phrenic nerve and inspiratory nuron in the cat. |
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Dong Ill Cho1, Hee Chul Han2,3, Sook Hyun Nohm2,3 |
1Department of Chest Medicine, National Medical Center, Seoul, Korea
2Department of Physiology, College of Medicine, Korea University , Seoul, Korea
3Neuroscience Research Institute, Korea University, Seoul, Korea |
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| Abstract |
Background
During movement the major inputs to nervous system come from firstly the muscle and joint to maintain posture and motion and secondly the chemoreceptors and baroreceptors to adjust the cardiovascular and respiratory function. Their complex relationships are generally studied for many years but the direct relation between the joint and respiratory system is not studied thoroughly until now. So this experiment was performed to determine whether the natural movement of knee joint can cause the enhancement of respiratory function by observation of the changes of respiratory rate, phrenic nerve activity and inspiratory neuron activity during the stimulation of knee joint in cat anesthetized with α-chloralose.
Methods
Twenty six male adult cats were used and the extracellular recording using bipolar platinum electrode and carbon filament electrode was done to record the changes in the activities of phrenic nerve and inspiratory neuron movement of knee joint, injection of chemicals into the joint cavity and electrical stimulation of articular nerve were done.
Results
The 60 Hz. could not but 120 Hz. flexion-extension movement of knee joint increased respiratory rate (R.R.), tidal neural activity (TNA), and minute neural activity (MNA). Intra-articular injection of lactate could not increase R.R. but significantly increase TNA and MNA which represented the enhanced respiratory function. Injection of potassium chloride showed similar effects with the case of lactate but the duration of effect was shorter. The electrical stimulation of medial articular nerve with IV strength which could activate only group 1 and II afferents showed increased TNA and MNA during stimulation but 20 V stimulation which could activate all the afferents increased all the respiratory parameters. The changes of inspiratory neuron activity by knee joint stimulation was similar to that of phrenic nerve.
Conclusion
The respiratory center could be directly stimulated by the activation of group 1 and II articular afferents and it seemed that the magnitude of the respiratory center enhancement is proportional to the amount of sensory information from the knee joint. These facts might suggest that the respiratory function could be enhanced even by the normal movement of knee joint. |
| Key Words:
Knee joint, phrenic nerve, inspiratory neuron |
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