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An Urban Experience
L. Radosta1
1Florida Veterinary Behavior Service, Veterinarian, West Palm Beach, USA
In general, psychotropic medications affect a relatively small group of neurotransmitters. Knowing the major functions and effects of inhibition and enhancement of transmission of these neurotransmitters is extremely helpful when prescribing medications.
Amino Acids
The amino acids are the workhorses of the brain neurotransmitters. Gamma-aminobutyric acid (GABA)
is the most widespread inhibitory neurotransmitter in
the brain. GABA is involved in the inhibition of vigilance, anxiety, muscle tension and memory enhancement. Glutamate works in an excitatory capacity in the brain.
It is the major mediator of excitatory signals in most aspects of normal brain functioning including cognition, memory and learning. The most commonly used veterinary medication classes which affects GABA are the benzodiazepines and anticonvulsant classes. Natural compounds which affect GABA are: alpha casozepine, magnolia officionalis, phellodendron amurese, souroubea, plantanus and l-theanine. L-theanine and magnolia-phellodendron combinations also act as glutamate antagonists. The products which contain these compounds are discussed in Making Medication Choices.
Gabapentin is an anticonvulsant, antineuralgic used for chronic pain and anxiety. It can e used as a sedative
for disorders which interrupt sleep or as a previsit pharmaceutical. It has it’s effect by closing presynaptic calcium channels thereby diminishing neuronal activity. It doesn’t have any action directly on GABA.
The monoamines include, but are not limited to norepinephrine, serotonin, and dopamine. These three neurotransmitters are concentrated in the hypothalamus, limbic system and other midbrain areas. There is a significant amount of overlap in the effects of these neurotransmitters on the behavior of animals. See Image 1 below.
In addition, the inhibition or enhanced release of one in many cases affects the release or inhibition of another. For example, a medication which only directly affects serotonin, can indirectly through the mechanism of inhibition or enhanced release of serotonin affect
   The monoamines can further be divided up into catecholamines and indoleamines. The catecholamines of interest are norepinephrine and dopamine. Norepinephrine affects alertness, concentration,
energy levels, anxiety, impulsivity and irritability as well as attention span. Dopamine in addition to affecting attention span, affects pleasure, reward, motivation, and drive.
Serotonin is an indoleamine. Similarly to norepinephrine, it affects anxiety, impulsivity, and irritability. In addition, if affects obsessive thoughts, compulsions and memory. Norepinephrine, dopamine, and serotonin are all involved in mood stabilization and cognitive function.
Knowing which medications affect which neurotransmitters can guide the practitioner as to how to make medication choices. It can also immediately give the veterinarian and idea of the potential side effects and interactions of that particular medication. See Image 2 and 3 below.

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