Investigation on the possible relationship existing between the HLA-DR gene and attention deficit hyperactivity disorder and/or mental retardation.

This study examines the possible relationship existing between the HLA-DR gene and attention deficit hyperactivity disorder (ADHD) and/or mental retardation (MR). The diagnosis of ADHD and mental retardation were established through clinical interviews with the parents, children and teachers, according to the criteria in DSM-IV. HLA-DRB1 genotyping was performed both by polymerase chain reaction-sequence specific primers (PCR-SSP) and by sequence based typing (SBT) in a cohort of 81 affected children and a sample of 100 healthy controls. Here, we report a positive association of HLA-DR4 with ADHD but not with MR. The study adds confirmation to the role of the HLA-DRB1 in the etiology of some types of childhood neuropsychiatric illnesses.

Phosphinic acid analogues of GABA. 2. Selective, orally active GABAB antagonists.

In 1987, 25 years after the synthesis of the potent and selective GABAB agonist baclofen (1), Kerr et al. described the first GABAB antagonist phaclofen 2. However, phaclofen and structurally similar derivatives 3-5 did not cross the blood-brain barrier and hence were inactive in vivo as central nervous system agents. As a consequence, the therapeutic potential of GABAB antagonists remained unclear. In exploring GABA and baclofen derivatives by replacing the carboxylic acid residue with various phosphinic acid groups, we discovered more potent and water soluble GABAB antagonists. Electrophysiological experiments in vivo demonstrated that some of the new compounds were capable of penetrating the blood-brain barrier after oral administration. Neurotransmitter release experiments showed that they interacted with several presynaptic GABAB receptor subtypes, enhancing the release of GABA, glutamate, aspartate, and somatostatin. The new GABAB antagonists interacted also with postsynaptic GABAB receptors, as they blocked late inhibitory postsynaptic potentials. They facilitated the induction of long-term potentiation in vitro and in vivo, suggesting potential cognition enhancing effects. Fifteen compounds were investigated in various memory and learning paradigms in rodents. Although several compounds were found to be active, only 10 reversed the age-related deficits of old rats in a multiple-trial one-way active avoidance test after chronic treatment. The cognition facilitating effects of 10 were confirmed in learning experiments in Rhesus monkeys. The novel GABAB antagonists showed also protective effects in various animal models of absence epilepsy.