Anticonvulsants inhibit rat neuronal somatostatin release

Cerebrospinal fluid somatostatin levels in febrile seizures and epilepsy in children

We analysed the level of cerebrospinal fluid (CSF) somatostatin in children with febrile seizures and epilepsy. In the febrile seizure group (n = 23), the somatostatin level was 83.9 +/- 11.2 pg/ml, which was significantly higher than that of age-matched controls. CSF samples obtained within 3 h of the last seizure had higher somatostatin levels (106.1 +/- 12.4 pg/ml;n = 14) than did the CSF obtained after 3 h (49.4 +/- 15.6 pg/ml;n = 9). The mean somatostatin level in the epilepsy group was 35.3 +/- 4.3 pg/ml (n = 34), and was distributed as follows: 27.6 +/- 3.6 pg/ml in the idiopathic generalized epilepsy group (n = 16), 44.0 +/- 9.4 pg/ml in the symptomatic generalized epilepsy group (n = 13), and 37.2 +/- 10.1 pg/ml in the partial epilepsy group (n = 5). The levels in each group were significantly higher than those in age-matched controls. Somatostatin is a hypothalamic tetradecapeptide with excitatory effects on neurons in children with febrile seizures and epilepsy. The finding that patients with convulsive disease had elevated levels of CSF somatostatin suggests that somatostatin release is somehow related to seizure activity. It remains to be determined whether this is due to increased release from over-active excitatory neurons or leakage from damaged or anoxic neurons, secondary to seizure activity.

Long-term changes in regional brain cytochrome oxidase activity induced by electroconvulsive treatment in rats

Quantitative cytochrome oxidase (CO) histochemistry was used to examine brain regional metabolic effects of electroconvulsive shock-induced seizures (ECS). Rats receive a course of either eight ECS or control treatments and were sacrificed either 24 h or 28 days after the last session. Regional CO activity (mumol/gT/min) was quantitated throughout the brain using internally calibrated standards. Twenty-four hours after the last ECS session there was no significant difference between ECS- and sham-treated brains in any of the 99 brain regions examined. In contrast, 28 days after the last session, ECS brains showed significant increases in CO activity in the interpeduncular nucleus (+20%), bed nucleus of the stria terminalis (+25%), dorsomedial hypothalamus (+20%), ventromedial hypothalamus (+12%), mammillary nucleus (+14%), pontine nucleus (+16%), basolateral amygdala (+14%), medial amygdala (+12%), piriform cortex (+12%) and ventromedial thalamus (+9%). These results suggest that ECS induces localized increases in brain CO activity which are long-lasting and may develop independently of additional stimulation. The fact that CO changes were predominantly in limbic areas suggests that they may be relevant to the antidepressant effects of ECS.