In experiments using pregnant rats, the following results were noted: (a) Of the amygdaloid kindled rats, the generalized seizure triggering threshold of the pregnant group was significantly higher than that of the nonpregnant group. (b) Of the rats taking oral phenobarbital, 4 mg/kg once a day, there was no significant difference of serum levels between the pregnant group and the nonpregnant group. (c) Of the amygdaloid kindled rats taking oral phenobarbital, 4 mg/kg once a day, the generalized seizure triggering threshold of the pregnant group was significantly higher than that of the nonpregnant group. It may be suggested that, when the drug dose remains the same, the rise in threshold by gestational physiological changes antagonizes the fall in threshold by decreased serum levels of anticonvulsants because of increasing distribution volume due to increasing body weight during pregnancy.

Animals↗

PubMedDate not supplied

Clinical study of oral administration of DN-1417, a TRH analog, in patients with intractable epilepsy.

An open dose-finding trial of orally administered DN-1417 was undertaken to investigate dose, efficacy, and adverse reactions. One hundred ninety patients, with epilepsy resistant to conventional drug treatment, were randomly allocated to two treatment groups of low dose (20 mg/day for adult) and high dose (80 mg/day for adult). Medication was given while fasting, once a day, for 8 weeks. If at the end of the first 4-week treatment period the patient had a satisfactory response, the dose was doubled. Patient response was assessed by global improvement rating (GIR) based on changes in seizure frequency, EEG findings, and nonparoxysmal clinical manifestations. The responses assessed by GIR was "slightly to markedly improved" in 48% of the patients with low-dose treatment and 55% with high-dose treatment. There was no clear dose-related difference between the two treatments. In patients with Lennox-Gastaut syndrome having no history of West syndrome, the rate of response assessed by GIR was found to be slightly dose-related (low dose, 61%; high dose, 73%).

Administration, Oral↗

PubMedDate not supplied

Important roles of N-methyl-D-aspartate receptors in expression of amygdaloid-kindled seizure demonstrated by intraperitoneal administration of L-aspartate in dimethyl sulfoxide.

Intraperitoneally (i.p.) administered L-aspartate (Asp) (20 mmol/kg) produced no behavioral or EEG change in nonkindled rats. Nonkindled rats that received 18, 19, or 20 mmol/kg Asp, dissolved in 10 or 15% dimethylsulfoxide (DMSO), i.p. developed masticatory movement, head nodding, and myoclonic jerks of the limbs, followed by wild running and subsequent tonic extension of the whole body. In contrast to the effects in nonkindled rats, i.p. injection of Asp 20 mmol/kg in 15% DMSO in amygdala-kindled rats precipitated electroclinical generalized seizures identical to kindled ones. When the kindled amygdala was pretreated with 2-amino-7-phosphonoheptanoic acid (2-APH), a potent and specific antagonist of N-methyl-D-aspartate (NMDA) receptors, the Asp/DMSO-induced generalized convulsion identical to kindled amygdala seizure was suppressed. 2-APH treatment of the contralateral amygdala was without such suppression. The results suggest that (a) Asp is ineffective when given alone (when given with DMSO, however, Asp evokes generalized seizures identical to kindled ones in amygdala-kindled rats, while it induces a qualitatively different generalized seizure in nonkindled rats; (b) NMDA receptors of the kindled amygdala play an important role in activation of the transsynaptic neurocircuit underlying the expression of kindled amygdala seizure; and (c) DMSO is useful in assessing potential central effects of compounds that do not readily penetrate the blood-brain barrier (BBB).

Amygdala↗

PubMedDate not supplied

Dexamethasone suppression test in schizophrenia: its relation to monoamine metabolism in hypothalamic-pituitary-adrenal axis.

The metabolic disturbances of monoamine in the hypothalamic-pituitary-adrenal axis (HPA axis) was examined in patients with chronic schizophrenia showing nonsuppression of the dexamethasone suppression test (DST). Subjects were 16 male chronic schizophrenics consisting of 8 DST suppressors and 8 nonsuppressors. All the patients were orally given the 5HT precursor, L-5-hydroxytryptophan (L-5HTP, 3 mg/kg) and the alpha 2-adrenergic agonist, clonidine (3 micrograms/kg), and the concentrations of plasma prolactin, cortisol, human growth hormone, and blood 5HT were measured chronologically. As a result, all of the DST nonsuppressors showed no increased response of prolactin after L-5HTP loading. Moreover, in the DST nonsuppressors, the secretion response of cortisol after L-5HTP loading was delayed compared with that of the suppressors. However, no different response between the DST suppressors and the nonsuppressors was observed after a loading dose of clonidine. These results suggest that there might be a metabolic disturbance of 5HT in the HPA axis of chronic schizophrenics showing DST nonsuppression.

5-Hydroxytryptophan↗