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Potentiation of hyperthermia-induced convulsions in the developing rat by previous treatment with pentylenetetrazol
Insights
Early exposure to pentylenetetrazol-induced seizures in infant rats primes them for hyperthermia-induced convulsions. This cross-sensitization suggests developing rat brains may have adult-like seizure susceptibility mechanisms.
Area of Science:
- Neuroscience
- Developmental Biology
- Pharmacology
Background:
- Immature mammalian nervous systems exhibit unique developmental trajectories.
- Seizure susceptibility can be influenced by various endogenous and exogenous factors during development.
Purpose of the Study:
- To investigate cross-sensitization between pentylenetetrazol-induced and hyperthermia-induced convulsions in developing rats.
- To examine the maturation of central nervous system substrates involved in seizure development.
Main Methods:
- Infant rats (5-13 days old) were repeatedly exposed to pentylenetetrazol-induced seizures.
- Seizure susceptibility to hyperthermia was assessed at 17 days of age.
- Acute administration of subconvulsive pentylenetetrazol doses was also evaluated.
Main Results:
- Prior pentylenetetrazol exposure significantly facilitated hyperthermia-induced convulsions.
- A subconvulsive dose of pentylenetetrazol also enhanced hyperthermia-induced seizure development.
- These findings indicate cross-sensitization between different convulsant agents in developing rats.
Conclusions:
- Cross-sensitization between convulsant agents is possible in the immature rat nervous system.
- The underlying neural mechanisms for seizure susceptibility appear to possess adult-like characteristics even in the developing brain.
Abstract:
Infant rats were subjected to pentylenetetrazol-induced convulsions on alternate days from 5 to 13 days of age. At 17 days of age, their susceptibility to the convulsant effects of hyperthermia was examined. It was found that previous pentylenetetrazol-induced convulsions caused a significant facilitation in the development of hyperthermia-induced convulsions. The development of hyperthermia-induced convulsions was also facilitated in rat pups of a similar age after acute pretreatment with a subconvulsive dose of pentylenetetrazol. The results of this study indicate that cross sensitization between convulsant agents is possible in the developing rat. In addition, although the nervous system of the immature rat is not fully developed, the central substrates of this process evince adultlike characteristics.