Abstract
In the pentobarbitone/urethane anaesthetized rabbit and pentobarbitone anaesthetized cat intratracheal inhalation of amyl nitrite, a non-specific smooth muscle relaxant, caused a vagally dependent depression of patellar reflex and spontaneous (thermal shivering and external intercostal inspiratory) motor activities. A prolonged vagally-independent potentiation succeeded the initial inhibition. The potentiation of intercostal activity may account for the increase in tidal volume produced by amyl nitrite after vagotomy. The patellar reflex potentiation survived thoracolumbar spinal transection but could not be attributed to a direct facilitation of neuromuscular or muscular events. A correlation existed between the relative dependence of fusimotor support of a muscle and its susceptibility to the inhibitory and subsequent facilitatory affects of amyl nitrite inhalation. The diaphragm and interchondral muscles, essentially independent of the autogenic facilitation provided by muscle spindles, demostrated neither of these effects. Conversely, the intercostal muscles depend greatly on such facilitation, as do the pectoral and limb muscles during thermal shivering.
Original language | English |
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Pages (from-to) | 181-193 |
Number of pages | 13 |
Journal | Respiration Physiology |
Volume | 62 |
Issue number | 2 |
DOIs | |
Publication status | Published - Nov 1985 |
Externally published | Yes |
Keywords
- Amyl nitrite
- Cat
- Interchondral muscles
- Intercostal muscles
- Patellar reflex
- Phrenic motoneurones
- Rabbit
- Shivering
- Vagus nerves