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Hyper-beta-alaninemia was found in a somnolent, convulsing infant. Hyper-beta-aminoaciduria (beta-ala, betaAIB and taurine) was also observed, varying directly with plasma beta-alanine concentration. The beta-aminoaciduria is explained by the interaction between beta-alanine and a specific cellular-transport system with preference for beta-amino compounds. Gamma-aminobutyricaciduria was also observed, its excretion being independent of beta-alanine levels. Dietary modifications, pyridoxine, pantothenic acid and antibiotic therapy were not beneficial. Post-mortem tissues had elevated levels of beta-alanine and carnosine; GABA levels in brain were probably elevated for the age of the patient. A proposed block in beta-alanine-alpha-ketoglutarate transaminase would expand the free beta-alanine pool, thus increasing tissue carnosine. beta-Alanine is a central-nervous-system depressant. Associated inhibition of GABA transaminase and displacement of GABA from central-nervous-system binding sites would produce GABAuria and convulsions.

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1 The effects of calcium antagonists on behaviour mediated by 5-hydroxytryptamine (5-HT) have been studied in rats and mice together with an investigation of the effects of these drugs on 5-HT synthesis in rat brain and endogenous 5-HT release from brain slices. 2 Administration of felodipine (35mg kg-i.p.) to rats pretreated with tranylcypromine (20mg kg-1, i.p.) resulted in the animals displaying the complete 5-HT-mediated behavioural syndrome (including head weaving, reciprocal forepaw treading and hind limb abduction) 75 min later. No evidence was obtained for the rate of 5-HT synthesis in brain regions differing between control and felodipine-treated rats. 3 Pretreatment with felodipine (10 or 35mg kg-1) enhanced the 5-HT-mediated behavioural syndrome induced by injection of tranylcypromine and L-tryptophan. The rate of 5-HT accumulation in the brain was similar in both groups. Administration of Bay K 8644 (1 mg kg 1, i.p.) did not prevent the enhanced behaviour induced by felodipine (lOmgkg-'). 4 The 5-HT behavioural syndrome induced by injection of the 5-HTlA agonist 8-hydroxy-2{di-n-propylamino)tetralin (8-OH-DPAT) was unaltered by either acute injection of felodipine (35 mg kg 1) or administration of felodipine twice daily for 3 days. 7 Hydralazine (5mg kg 1, i.p.) induced the 5-HT behavioural syndrome in tranylcypromine pretreated rats, enhanced the tranylcypromine/L-tryptophan behavioural syndrome, inhibited 5-MeODMT-induced head twitch behaviour in mice and was not a 5-HT2 receptor antagonist. 8 These data indicate that at a high dose, Ca2+ antagonists produce complex changes in 5-HT function in rodents which are similar to those produced by lithium administration. The data with hydralazine suggest that the effects seen are not related to an action at Ca2 + channels. IntroductionRecently Boullin & Grahame-Smith (1987) In both tests the behavioural changes (head weaving, forepaw treading and flat body posture) were measured on a 0-3 score (0: absent, 1: just present; 2: present; 3: severe) as described previously (Deakin & Green, 1978;Goodwin & Green, 1985 Ltd, 1990 42 A.R. GREEN et al.However, in other experiments results are given as the combined behavioural score 40, 60 and 80min after injection and the total score of all 3 observation times. This 'shortened' observation scoring nevertheless reflected the overall pattern of behavioural change.5-HT2 receptor-mediated responses were examined following agonist administration to mice by measurement of the resultant head-twitch response as described in detail previously (Goodwin & Green, 1985). Briefly, mice were injected with 5-MeODMT (5mgkg-1, i.p.) and the total number of head twitches counted in the next 5min. Because of some variability in the response from day to day, control (vehicle injected) animals were always examined with the experimental group and to simplify presentation, results are given as the percentage inhibition of the experimental response compared to the appropriate control group. Tissue extractionIn experiments examining th...