Biomedical subjects

C E Reigel

Publications and source records attributed to C E Reigel.

22 records · Page 2Linked to original sources

PubMedDate not supplied

Sex-specific distinctions in audiogenic convulsions exhibited by severe seizure genetically epilepsy-prone rats (GEPR-9s).

The severe seizure genetically epilepsy-prone rat (GEPR-9) is characterized by a broad-based seizure predisposition and is increasingly recognized as a useful model of epilepsy. When sound stimulated, members of the GEPR-9 colony exhibit complete tonic extensor convulsions. Female GEPR-9s appear to experience a higher frequency of more severe seizures than males when they are sound stimulated. The purpose of this report is to examine and document this observation. Convulsive behavior was evaluated in approximately 4400 GEPR-9s. Each of these animals was sound stimulated 3 times at weekly intervals. Audiogenic response score (ARS), latency to wild running and latency to convulsion were recorded for each animal in each of the 3 tests. For the first 2 weekly tests, females exhibited a significantly higher incidence of complete tonic convulsions, a significantly higher ARS and significantly shorter latencies to wild running and convulsions than did males. The significant differences in latencies persisted through the 3 tests, whereas an increase in the incidence of complete tonic convulsions among males led to a diminution of the differences between males and females in the other parameters. The possible underlying biochemical differences that are responsible for this sex difference in seizure severity are, as yet, unknown.

Acoustic Stimulation↗

PubMedDate not supplied

Audiogenic convulsions in moderate seizure genetically epilepsy-prone rats (GEPR-3s).

The moderate seizure genetically epilepsy-prone rat (GEPR-3) typically exhibits a generalized clonic convulsion upon acoustical stimulation. The purpose of this report is to document sex-specific distinctions in the seizure characteristics as well as the effect of prior seizure experience on sensitivity to acoustically induced seizures in members of the GEPR-3 colony. Convulsive behavior was evaluated in approximately 3300 GEPR-3s. Each of these animals was stimulated with sound 3 times at weekly intervals. Audiogenic response score (ARS), latency to the onset of wild running and latency to convulsion were recorded for each animal in each of 3 tests given at 1 week intervals. Statistical analysis revealed that compared to their male littermates, females exhibited significantly shorter latencies to onset of running and convulsion for the last of the 3 weekly tests. Also, in both sexes, a significantly higher incidence of clonic convulsions, an increase in audiogenic response scores and a reduction in latencies to running and convulsion were observed in each succeeding audiogenic stimulation test. The mechanism of this increased seizure facilitation with prior seizure experience may have at least some similarity to that of kindling. The factors responsible for sex-specific distinctions in seizure severity are unknown at the present time.

Acoustic Stimulation↗

PubMedDate not supplied

Ontogeny of sound-induced seizures in the genetically epilepsy-prone rat.

Seizure responsiveness of the adult genetically epilepsy-prone rat (GEPR) is well documented. Much less is known about the ontogeny to seizure activity in the GEPR. In the present study, members of the moderate seizure (GEPR-3) and severe seizure (GEPR-9) colonies were tested for susceptibility to sound-induced seizures at 11 different ages ranging from 13 to 45 days post partum. Running episodes first appeared in GEPR-3s at 15 days post partum. Clonic seizures first appeared in GEPR-3s and GEPR-9s at 15 and 16 days post partum, respectively. Seizure incidence reached 100% by post partum day 21 in both colonies. GEPR-3s exhibited a 100% incidence of their characteristic clonic seizure at day 21. GEPR-9s exhibited a 77.3% incidence of clonic seizure and a 22.7% incidence of their adult characteristic tonic seizure at day 21. Tonic seizures first appeared in GEPR-9s at day 18 and increased in incidence over time reaching 100% by day 45. Two unexpected findings occurred in GEPR-3s. First, secondary rearing seizures were detected in all GEPR-3s exhibiting clonic seizures between day 16 and 21. Second, GEPR-3s exhibited a transient susceptibility between 19 and 27 days post partum to the more severe tonic seizures characteristic of adult GEPR-9s. Peak incidence of tonic seizures in GEPR-3s was 70%, occurring at day 23. The adult GEPR-3 pattern of 100% incidence of clonic seizures was restored by day 45.

Acoustic Stimulation↗

PubMedDate not supplied

Neurobiology of seizure predisposition in the genetically epilepsy-prone rat.

Seizure predisposition in the genetically epilepsy-prone rat (GEPR) is innately determined and these animals exhibit consistent and reproducible convulsive patterns. This epilepsy model is made up of 2 independently derived colonies of animals with each exhibiting a characteristic convulsive pattern. In response to a standardized acoustic stimulus, GEPR-3s exhibit moderate or clonic convulsions and GEPR-9s exhibit more severe tonic extensor convulsions. Besides exhibiting convulsions in response to sound stimulation, some GEPRs experience spontaneous and hyperthermic seizures. They are also abnormally sensitive to a number of seizure provoking stimuli that produce seizures in normal animals. The neurochemical basis for the seizure predisposition in GEPRs is increasingly well understood. Abnormalities in central nervous system norepinephrine and serotonin are widespread and may play a prominent role in regulation of seizures in the GEPR. Amino acid neurotransmitter systems are less well defined in the GEPR but abnormalities exist and may be, along with other documented deficiencies, responsible in part for the seizure predisposition that is characteristic of GEPRs.

Acoustic Stimulation↗