RESUMO
GABA, the major inhibitory neurotransmitter in the brain, is synthesized from L-glutamate and packaged within a family of highly differentiated inhibitory interneurons. Individual GABA inhibitory interneurons in the frontal cortex can make terminal synaptic connections with more than 200 distinct pyramidal neurons, the principal output neuron. Moreover, the sites of these synaptic connections include shafts of dendritic spines, soma, dendritic branches, and initial axon segments. The phasic activity of GABAergic neurons regulate intermittent oscillations of assemblies of pyramidal cell neurons, which are critical for many higher cortical functions such as working memory. Potentially, there are several viable pharmacotherapeutic strategies for facilitating GABAergic neurotransmission. A major research question is whether tonically-administered, selective GABAergic therapeutic interventions can mimic and correct disruptions of the intermittent oscillatory activity of assemblies of cortical pyramidal cell neurons.
Assuntos
Lobo Frontal/metabolismo , Interneurônios/metabolismo , Inibição Neural , Teoria Psicológica , Células Piramidais/metabolismo , Esquizofrenia/metabolismo , Transmissão Sináptica , Ácido gama-Aminobutírico/metabolismo , Animais , Axônios/metabolismo , Relógios Biológicos/efeitos dos fármacos , Carisoprodol/metabolismo , Dendritos/metabolismo , Espinhas Dendríticas/metabolismo , Lobo Frontal/efeitos dos fármacos , Agonistas GABAérgicos/farmacologia , Antagonistas GABAérgicos/farmacologia , Humanos , Memória , Inibição Neural/efeitos dos fármacos , Esquizofrenia/tratamento farmacológico , Transmissão Sináptica/efeitos dos fármacosRESUMO
Pain, spasticity, tremor, spasms, poor sleep quality, and bladder and bowel dysfunction, among other symptoms, contribute significantly to the disability and impaired quality of life of many patients with multiple sclerosis (MS). Motor symptoms referable to the basal ganglia, especially paroxysmal dystonia, occur rarely and contribute to the experience of distress. A substantial percentage of patients with MS report subjective benefit from what is often illicit abuse of extracts of the Cannabis sativa plant; the main cannabinoids include delta-9-tetrahydrocannabinol (delta9-THC) and cannabidiol. Clinical trials of cannabis plant extracts and synthetic delta9-THC provide support for therapeutic benefit on at least some patient self-report measures. An illustrative case is presented of a 52-year-old woman with MS, paroxysmal dystonia, complex vocal tics, and marijuana dependence. The patient was started on an empirical trial of dronabinol, an encapsulated form of synthetic delta9-THC that is usually prescribed as an adjunctive medication for patients undergoing cancer chemotherapy. The patient reported a dramatic reduction of craving and illicit use; she did not experience the "high" on the prescribed medication. She also reported an improvement in the quality of her sleep with diminished awakenings during the night, decreased vocalizations, and the tension associated with their emission, decreased anxiety and a decreased frequency of paroxysmal dystonia.