Imaging of CB1 Receptors Using (11C)SD5024
Palavras-chave
Resumo
Descrição
The cannabinoid type 1 (CB(1)) receptor is one of the most abundant G protein-coupled receptors in the brain (Matsuda et al 1990). It is found on glutamatergic, dopaminergic, and gamma aminobutyric acid (GABA)-ergic synaptic terminals and mediates the effects of endocannabinoids (ECs), which suppresses the release of neurotransmitters. The CB(1) receptor is a target for drug therapy, including the use of a CB(1) receptor antagonist as an appetite suppressant. Our laboratory recently developed a promising positron emission tomography (PET) ligand for the CB(1) receptor: [(11)C]SD5024 (Donohue et al 2008a).
Previous studies from our laboratory used two PET ligands to image CB(1) receptors (11)C-MePPEP and (18)F-FMPEP-d(2) (Yasuno et al 2008; Donohue et al 2008b) and found that the latter provides more accurate and precise measurement. We also found that clearance of (11)C-MePPEP from brain was too slow for (11)C-labeling (Terry et al 2010). Although we are currently using [(18)F]FMPEP-d(2) , the major disadvantage of the current radioligand is that it washes out slowly from the brain, and accurate quantitation requires relatively fast washout. If [(11)C]SD5024 is amenable to quantitation in human subjects, then it may prove to be a useful ligand for studying potential pathophysiological changes of this receptor.
The purpose of this protocol is (1) to perform brain imaging using [(11)C]SD5024 in healthy volunteers to characterize brain uptake and distribution; (2) to perform whole body PET studies in healthy volunteers in order to estimate radiation absorbed doses for [(11)C]SD5024; and (3) to perform brain test-retest studies in healthy volunteers to further examine how precise measurements of receptor binding are, and to determine optimal parameters for future experiments using [(11)C]SD5024.
Successful development of a PET radioligand to image CB1 receptors has the potential to significantly impact our understanding and clinical management of neuropsychiatric (eg, schizophrenia) (Eggan et al 2008) and metabolic (eg, obesity) (Gazzerro et al 2007) disorders. Future experiments would include studies of relevant neuropsychiatric disorders.
datas
| Última verificação: | 12/17/2013 |
| Enviado pela primeira vez: | 07/19/2011 |
| Inscrição estimada enviada: | 07/19/2011 |
| Postado pela primeira vez: | 07/20/2011 |
| Última atualização enviada: | 11/26/2019 |
| Última atualização postada: | 11/28/2019 |
| Data real de início do estudo: | 06/21/2011 |
| Data Estimada de Conclusão Primária: | 12/17/2013 |
| Data Estimada de Conclusão do Estudo: | 12/17/2013 |
Condição ou doença
Intervenção / tratamento
Procedure: Brain Scan-PET
Procedure: Brain Scan-MRI
Procedure: Arterial Line
Procedure: Venous Line
Procedure: Blood Sampling
Fase
Critério de eleição
| Idades qualificadas para estudar | 18 Years Para 18 Years |
| Sexos elegíveis para estudo | All |
| Aceita Voluntários Saudáveis | sim |
| Critério | - INCLUSION CRITERIA: Healthy control subjects aged 18 50 whose medical history, physical exam, electrocardiogram (ECG), and laboratory test results are within normal limits within one year of the PET scan will be eligible to participate. EXCLUSION CRITERIA: Any recent or past history of psychiatric illness or severe systemic disease based on history and physical exam. Serious medical illness likely to modify brain anatomy and/or physiology (head trauma, past brain surgery, neurological disorders such as epilepsy, Parkinson disease, and psychiatric disorders such as schizophrenia and depression) Any current substance or alcohol abuse, with the exception of nicotine. Positive urine toxicology screen Radiation exposure from participation in other research protocols in the last year such that the additional radiation exposure from this protocol would exceed annual limits. Pregnant or breastfeeding. Claustrophobia (applies to Parts 1 and 3 only). Metallic (ferromagnetic) implants, including pacemakers or other implanted electrical devices, brain stimulators, some types of dental implants, aneurysm clips (metal clips on the wall of a large artery), metallic prostheses (including metal pins and rods, heart valves, and cochlear implants), permanent eyeliner, implanted delivery pump, shrapnel fragments, and possible small metal fragments in the eye (applies to Parts 1 and 3 only). Unable to lie flat on back for up to 2.5 hours. |
Resultado
Medidas de Resultado Primário
1. For the PET scans, we will measure the regional densities of cannabinoid 1 receptors as distribution volume (VT). Distribution volume is the ratio at equilibrium of brain uptake to the concentration of parent radioligand in plasma. [undefined]
