Question: where are cannabinoid receptors located in the brain
[{'answer': 'central nervous system', 'provenance': [{'wikipedia_id': '586091', 'title': 'Cannabinoid receptor', 'start_paragraph_id': 3, 'start_character': 133, 'end_paragraph_id': 3, 'end_character': 155, 'bleu_score': 1.0, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '586091', 'title': 'Cannabinoid receptor', 'start_paragraph_id': 3, 'start_character': 0, 'end_paragraph_id': 3, 'end_character': 560, 'bleu_score': 0.932083220007442, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3744703404542850382}, 'section': 'Section::::Abstract.'}]}]