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[Behavioral and EEG alterations with brain stem compression and effect of thyrotropin-releasing hormone (TRH) in
Insights
Thyrotropin-releasing hormone (TRH) significantly improved behavioral and EEG changes in cats experiencing brain stem compression. TRH administration aided recovery from altered consciousness and neurological deficits.
Area of Science:
- Neuroscience
- Neurophysiology
Context:
- Brain stem compression can induce significant behavioral and electroencephalogram (EEG) alterations, mimicking clinical disturbances in consciousness.
- Understanding the neurological impact of brain stem compression is crucial for developing therapeutic interventions.
Purpose:
- To investigate the behavioral and EEG effects of acute brain stem compression in cats.
- To evaluate the therapeutic potential of thyrotropin-releasing hormone (TRH) in mitigating these compression-induced neurological deficits.
Summary:
- Cats subjected to controlled brain stem compression exhibited distinct behavioral changes (e.g., immobility, spastic extension) and abnormal EEG patterns (e.g., flattened, spike, slow waves).
- Intravenous administration of TRH led to remarkable improvements in both behavioral recovery and EEG patterns, including prompt shifts in posture and persistent EEG arousal.
- TRH demonstrated a dose-dependent effect, ameliorating the neurological deterioration associated with brain stem compression.
Impact:
- This study highlights TRH as a potential therapeutic agent for conditions involving brain stem dysfunction and altered consciousness.
- The findings provide valuable insights into the neuroprotective mechanisms of TRH and its role in managing neurological emergencies.
Abstract:
Behavioral and EEG changes induced by brain stem compression and the effect of TRH were studied. The compression was given for 1 to 6 min by inflating a balloon chronically implanted on the dorsal surface of the cat brain stem in the 4th ventricle via cisterna magna. Within 10 to 36 sec after the start of the compression, the cats turned sideways and became motionless in a spastic extension of four legs, and thereafter all reverted to a normal position, after 45 to 120 min, although slight movements or head-up position was observed in some animals. The cortical EEG patterns observed after the compression were initially a brief rush of low amplitude-fast waves (EEG arousal) followed by a flattened and/or spike pattern, and subsequently these shifted to high amplitude-slow waves with or without an accompanying EEG arousal. These behavioral EEG alterations were remarkably improved by i.v. administration of TRH as follows: eight of 12 cats with 1 mg/kg and one of 4 cats with 0.5 mg/kg promptly changed from the lateral to a crouching or abdominal position, and thereafter never turned sideways again. Partial recovery such as movements of forelegs, struggling or head-up in the lateral position, rolling or slight shift of position was also observed within several min in three cats with 1 mg/kg as well as in two cats with 0.5 mg/kg. Furthermore, TRH induced a dose dependent, persistent EEG arousal in all cats. These results show that TRH ameliorates deterioration in behavior and the EEG, this deterioration being similar to clinical states of disturbance in consciousness induced by compressing the brain stem.