Abstract
This chapter explores the use of drugs for veterinary mental health care and behavior modification. It focuses on amino acid neurotransmitters. In addition to their role in intermediary metabolism, certain amino acids function as small molecule neurotransmitters in the central and peripheral nervous systems. Application of excitatory amino acids such as glutamic acid and aspartic acid typically depolarize mammalian neurons, while inhibitory amino acids such as gamma aminobutyric acid (GABA) and glycine characteristically hyperpolarize neurons. Ketamine is an anesthetic agent that was first introduced in clinical trials in the 1960s. Upon activation, the GABAergic neurons release GABA from presynaptic terminals into the synaptic cleft. GABAergic systems serve important regulatory functions in the brain such as vigilance, anxiety, muscle tension, epileptogenic activity, and memory.