* Neurogen Corp., of Branford, Conn., said its corporate partners, Pfizer Inc., of New York, and American Home Products Corp., of Madison, N.J., began Phase I trials with Neurogen's drugs for anxiety and epilepsy, respectively. Pfizer is developing Neurogen's NGD 91-2, which is described as a non-sedating, non-addictive small molecule compound that acts as an agonist to the gamma aminobutyric acid (GABA) receptors in the brain. Low levels of the GABA neurotransmitter are associated with anxiety and insomnia. American Home Products' subsidiary, Wyeth-Ayerst Laboratories, of King of Prussia, Pa., launched a Phase I trial in France of ADCI. The drug, Neurogen said, combines an antagonist of N-methyl-D-asparate (NMDA) receptors in the brain with "a use-dependent blocker of voltage-gated sodium channels" to treat epileptic seizures.