Platelet MAO activity in clinical subtypes of depression and DST suppression.

Platelet MAO activity was measured in 75 hospitalized depressed patients and in 31 healthy subjects. Plasmas post dexamethasone cortisol levels were examined in 73 patients. Results indicate that higher platelet MAO activity does not occur in all, but only in male major depressed patients.

2-Amino-6-trifluoromethoxy benzothiazole, a possible antagonist of excitatory amino acid neurotransmission--II. Biochemical properties.

Two models have been chosen to study the effect of 2-amino-6-trifluoromethoxy benzothiazole (PK 26124) on excitatory amino acid neurotransmission: the pool of cyclic guanosine monophosphate (cGMP) in the cerebellum and the release of acetylcholine in the striatum and olfactory tubercles. The release of acetylcholine induced by N-methyl-DL-aspartate in the striatum and olfactory tubercles was antagonized by PK 26124 which was less potent on the release of acetylcholine induced electrically. The increase in levels of cGMP in the cerebellum induced by excitatory amino acids such as glutamate and quisqualate was antagonized by PK 26124, but the drug was inactive against N-methyl-DL-aspartate, L-aspartate, kainate and cysteine sulphinate.

[Platelet monoamine oxidase and sex hormones in a population of depressed patients].

The association between changes in platelet MAO activity and Major Depressive Episode have been demonstrated. Cyclical changes in sex hormones serum levels had never been related with changes of MAO activity in depressed patients. Platelet MAO activity, oestrogen serum levels, progesterone serum levels and testosterone serum levels, have been measured in drug free depressed patients: 22 men and 42 women.

The 5-hydroxytryptamine-releasing properties of two epimer quinoline derivatives.

Two epimer quinoline derivatives, PK 5078 and PK 7059, have been shown to be potent at releasing 5-HT from blood platelets. Moreover PK 5078 was also a potent and selective inhibitor of the uptake of 5-HT, being about 20 times as active as clomipramine. Both drugs, like p-chloroamphetamine, released 5-HT but did not inhibit MAO-A.

A subacute treatment of L-methionine induces an increase in the number of [3H]spiperone binding sites in the striatum of the rat.

A subacute treatment, 500 mg/kg I.P. twice daily during 5 days, by L-methionine provoked an increase in the Bmax of [3H]-spiperone binding in the striatum of the rat.

Central dopaminergic neurons during development of genetic and DOCA-salt hypertension in the rat.

The in vivo binding of [3H]spiroperidol was measured in discrete areas of the brain in 7-, 9- and 16-week-old spontaneously hypertensive rats (SHR) and age-matched normotensive Wistar-Kyoto (WKY) controls. An increase in the [3H]spiroperidol binding in the striatum, tuberculum olfactorium and frontal cortex but not in the cerebellum was detected at all ages in SHR. The increase was more pronounced in 7- than in 9- or 16-week-old SHR.

Relationships between plasma corticosteroids and benzodiazepines in stress.

Forcing a rat to swim in a situation from which there is no escape results in an increase in plasma corticosteroid level. This rise was selectively inhibited by benzodiazepines, phenobarbital and meprobamate but not by other psychotropic drugs like trycyclic antidepressants, monoamine oxidase inhibitors, neuroleptics and amphetamines. This effect of benzodiazepines is of central origin since diazepam did not block the rise in plasma corticosteroid level produced by adrenocorticotrophic hormone.