Heterocyclic Compounds, 3-Ring/metabolism; Hydrocarbons, Cyclic/metabolism; Imines/metabolism; Marine Toxins/metabolism; Microalgae/chemistry; Pyrans/metabolism; Shellfish Poisoning/metabolism; Shellfish/toxicity; Spiro Compounds/metabolism; Animals; Binding Sites; Biological Assay; Cell Survival/drug effects; Food Contamination; Heterocyclic Compounds, 3-Ring/chemistry; Heterocyclic Compounds, 3-Ring/toxicity; Humans; Hydrocarbons, Cyclic/chemistry; Hydrocarbons, Cyclic/toxicity; Imines/chemistry; Imines/toxicity; Injections, Intraperitoneal; Marine Toxins/chemistry; Marine Toxins/toxicity; Mice; Muscarinic Antagonists/chemistry; Muscarinic Antagonists/metabolism; Muscarinic Antagonists/toxicity; Nicotinic Antagonists/chemistry; Nicotinic Antagonists/metabolism; Nicotinic Antagonists/toxicity; Protein Binding; Pyrans/chemistry; Pyrans/toxicity; Receptors, Muscarinic/metabolism; Receptors, Nicotinic/metabolism; Shellfish Poisoning/physiopathology; Spiro Compounds/chemistry; Spiro Compounds/toxicity; Structure-Activity Relationship