Receptors, Odorant: Proteins, usually projecting from the cilia of olfactory receptor neurons, that specifically bind odorant molecules and trigger responses in the neurons. The large number of different odorant receptors appears to arise from several gene families or subfamilies rather than from DNA rearrangement.Odors: The volatile portions of substances perceptible by the sense of smell. (Grant & Hackh's Chemical Dictionary, 5th ed)Smell: The ability to detect scents or odors, such as the function of OLFACTORY RECEPTOR NEURONS.Olfactory Receptor Neurons: Neurons in the OLFACTORY EPITHELIUM with proteins (RECEPTORS, ODORANT) that bind, and thus detect, odorants. These neurons send their DENDRITES to the surface of the epithelium with the odorant receptors residing in the apical non-motile cilia. Their unmyelinated AXONS synapse in the OLFACTORY BULB of the BRAIN.Olfactory Mucosa: That portion of the nasal mucosa containing the sensory nerve endings for SMELL, located at the dome of each NASAL CAVITY. The yellow-brownish olfactory epithelium consists of OLFACTORY RECEPTOR NEURONS; brush cells; STEM CELLS; and the associated olfactory glands.Olfactory Pathways: Set of nerve fibers conducting impulses from olfactory receptors to the cerebral cortex. It includes the OLFACTORY NERVE; OLFACTORY BULB; OLFACTORY TRACT; OLFACTORY TUBERCLE; ANTERIOR PERFORATED SUBSTANCE; and OLFACTORY CORTEX.Olfactory Bulb: Ovoid body resting on the CRIBRIFORM PLATE of the ethmoid bone where the OLFACTORY NERVE terminates. The olfactory bulb contains several types of nerve cells including the mitral cells, on whose DENDRITES the olfactory nerve synapses, forming the olfactory glomeruli. The accessory olfactory bulb, which receives the projection from the VOMERONASAL ORGAN via the vomeronasal nerve, is also included here.Olfactory Perception: The process by which the nature and meaning of olfactory stimuli, such as odors, are recognized and interpreted by the brain.Arthropod Antennae: Paired sense organs connected to the anterior segments of ARTHROPODS that help them navigate through the environment.Pentanols: Isomeric forms and derivatives of pentanol (C5H11OH).BenzaldehydesSensilla: Collective name for a group of external MECHANORECEPTORS and chemoreceptors manifesting as sensory structures in ARTHROPODS. They include cuticular projections (setae, hairs, bristles), pores, and slits.Monoterpenes: Compounds with a core of 10 carbons generally formed via the mevalonate pathway from the combination of 3,3-dimethylallyl pyrophosphate and isopentenyl pyrophosphate. They are cyclized and oxidized in a variety of ways. Due to the low molecular weight many of them exist in the form of essential oils (OILS, VOLATILE).Olfactory Marker Protein: A ubiquitous, cytoplasmic protein found in mature OLFACTORY RECEPTOR NEURONS of all VERTEBRATES. It is a modulator of the olfactory SIGNAL TRANSDUCTION PATHWAY.Receptors, Pheromone: Cell surface receptors that respond to PHEROMONES.Olfactory Nerve: The 1st cranial nerve. The olfactory nerve conveys the sense of smell. It is formed by the axons of OLFACTORY RECEPTOR NEURONS which project from the olfactory epithelium (in the nasal epithelium) to the OLFACTORY BULB.Sex Attractants: Pheromones that elicit sexual attraction or mating behavior usually in members of the opposite sex in the same species.Hexanols: Isomeric forms and derivatives of hexanol (C6H11OH).Eugenol: A cinnamate derivative of the shikamate pathway found in CLOVE OIL and other PLANTS.Nasal Cavity: The proximal portion of the respiratory passages on either side of the NASAL SEPTUM. Nasal cavities, extending from the nares to the NASOPHARYNX, are lined with ciliated NASAL MUCOSA.Pentanoic AcidsExplosive Agents: Substances that are energetically unstable and can produce a sudden expansion of the material, called an explosion, which is accompanied by heat, pressure and noise. Other things which have been described as explosive that are not included here are explosive action of laser heating, human performance, sudden epidemiological outbreaks, or fast cell growth.Anopheles gambiae: A species of mosquito in the genus Anopheles and the principle vector of MALARIA in Africa.Insect Repellents: Substances causing insects to turn away from them or reject them as food.Cyclohexenes: Six-carbon alicyclic hydrocarbons which contain one or more double bonds in the ring. The cyclohexadienes are not aromatic, in contrast to BENZOQUINONES which are sometimes called 2,5-cyclohexadiene-1,4-diones.Stimulation, Chemical: The increase in a measurable parameter of a PHYSIOLOGICAL PROCESS, including cellular, microbial, and plant; immunological, cardiovascular, respiratory, reproductive, urinary, digestive, neural, musculoskeletal, ocular, and skin physiological processes; or METABOLIC PROCESS, including enzymatic and other pharmacological processes, by a drug or other chemical.Insect Proteins: Proteins found in any species of insect.Sense Organs: Specialized organs adapted for the reception of stimuli by the NERVOUS SYSTEM.Volatilization: A phase transition from liquid state to gas state, which is affected by Raoult's law. It can be accomplished by fractional distillation.Aldehydes: Organic compounds containing a carbonyl group in the form -CHO.Octanols: Isomeric forms and derivatives of octanol (C8H17OH).Sensory Receptor Cells: Specialized afferent neurons capable of transducing sensory stimuli into NERVE IMPULSES to be transmitted to the CENTRAL NERVOUS SYSTEM. Sometimes sensory receptors for external stimuli are called exteroceptors; for internal stimuli are called interoceptors and proprioceptors.Pheromones: Chemical substances, excreted by an organism into the environment, that elicit behavioral or physiological responses from other organisms of the same species. Perception of these chemical signals may be olfactory or by contact.Santalum: A plant genus of the family SANTALACEAE which is the source of sandalwood oil.DEET: A compound used as a topical insect repellent that may cause irritation to eyes and mucous membranes, but not to the skin.Perfume: A substance, extract, or preparation for diffusing or imparting an agreeable or attractive smell, especially a fluid containing fragrant natural oils extracted from flowers, woods, etc., or similar synthetic oils. (Random House Unabridged Dictionary, 2d ed)Sensory Thresholds: The minimum amount of stimulus energy necessary to elicit a sensory response.Receptors, Ionotropic Glutamate: A class of ligand-gated ion channel receptors that have specificity for GLUTAMATE. They are distinct from METABOTROPIC GLUTAMATE RECEPTORS which act through a G-protein-coupled mechanism.KetonesNasal Mucosa: The mucous lining of the NASAL CAVITY, including lining of the nostril (vestibule) and the OLFACTORY MUCOSA. Nasal mucosa consists of ciliated cells, GOBLET CELLS, brush cells, small granule cells, basal cells (STEM CELLS) and glands containing both mucous and serous cells.Drosophila melanogaster: A species of fruit fly much used in genetics because of the large size of its chromosomes.Anisoles: A group of compounds that are derivatives of methoxybenzene and contain the general formula R-C7H7O.Olfaction Disorders: Loss of or impaired ability to smell. This may be caused by OLFACTORY NERVE DISEASES; PARANASAL SINUS DISEASES; viral RESPIRATORY TRACT INFECTIONS; CRANIOCEREBRAL TRAUMA; SMOKING; and other conditions.Ictaluridae: A family of North American freshwater CATFISHES. It consists of four genera (Ameiurus, Ictalurus, Noturus, Pylodictis,) comprising several species, two of which are eyeless.Terpenes: A class of compounds composed of repeating 5-carbon units of HEMITERPENES.Multigene Family: A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)Discrimination (Psychology): Differential response to different stimuli.Phenylethyl Alcohol: An antimicrobial, antiseptic, and disinfectant that is used also as an aromatic essence and preservative in pharmaceutics and perfumery.Lipocalin 1: A lipocalin that was orignally characterized from human TEARS. It is expressed primarily in the LACRIMAL GLAND and the VON EBNER GLANDS. Lipocalin 1 may play a role in olfactory transduction by concentrating and delivering odorants to the ODORANT RECEPTORS.Trinitrotoluene: A 2,4,6-trinitrotoluene, which is an explosive chemical that can cause skin irritation and other toxic consequences.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Chemoreceptor Cells: Cells specialized to detect chemical substances and relay that information centrally in the nervous system. Chemoreceptor cells may monitor external stimuli, as in TASTE and OLFACTION, or internal stimuli, such as the concentrations of OXYGEN and CARBON DIOXIDE in the blood.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Genes, Insect: The functional hereditary units of INSECTS.Thioglycolates: Organic esters of thioglycolic acid (HS-CH2COOH).Methyl n-Butyl Ketone: An industrial solvent which causes nervous system degeneration. MBK is an acronym often used to refer to it.Behavior, Animal: The observable response an animal makes to any situation.Habituation, Psychophysiologic: The disappearance of responsiveness to a repeated stimulation. It does not include drug habituation.Complex Mixtures: Mixtures of many components in inexact proportions, usually natural, such as PLANT EXTRACTS; VENOMS; and MANURE. These are distinguished from DRUG COMBINATIONS which have only a few components in definite proportions.Electrophysiology: The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.Vomeronasal Organ: An accessory chemoreceptor organ that is separated from the main OLFACTORY MUCOSA. It is situated at the base of nasal septum close to the VOMER and NASAL BONES. It forwards chemical signals (such as PHEROMONES) to the CENTRAL NERVOUS SYSTEM, thus influencing reproductive and social behavior. In humans, most of its structures except the vomeronasal duct undergo regression after birth.Axons: Nerve fibers that are capable of rapidly conducting impulses away from the neuron cell body.Air Movements: The motion of air currents.Cilia: Populations of thin, motile processes found covering the surface of ciliates (CILIOPHORA) or the free surface of the cells making up ciliated EPITHELIUM. Each cilium arises from a basic granule in the superficial layer of CYTOPLASM. The movement of cilia propels ciliates through the liquid in which they live. The movement of cilia on a ciliated epithelium serves to propel a surface layer of mucus or fluid. (King & Stansfield, A Dictionary of Genetics, 4th ed)Cyclohexanols: Monohydroxy derivatives of cyclohexanes that contain the general formula R-C6H11O. They have a camphorlike odor and are used in making soaps, insecticides, germicides, dry cleaning, and plasticizers.Neuropil: A dense intricate feltwork of interwoven fine glial processes, fibrils, synaptic terminals, axons, and dendrites interspersed among the nerve cells in the gray matter of the central nervous system.ButanonesMoths: Insects of the suborder Heterocera of the order LEPIDOPTERA.GTP-Binding Protein alpha Subunits: The GTPase-containing subunits of heterotrimeric GTP-binding proteins. When dissociated from the heterotrimeric complex these subunits interact with a variety of second messenger systems. Hydrolysis of GTP by the inherent GTPase activity of the subunit causes it to revert to its inactive (heterotrimeric) form. The GTP-Binding protein alpha subunits are grouped into families according to the type of action they have on second messenger systems.Ligands: A molecule that binds to another molecule, used especially to refer to a small molecule that binds specifically to a larger molecule, e.g., an antigen binding to an antibody, a hormone or neurotransmitter binding to a receptor, or a substrate or allosteric effector binding to an enzyme. Ligands are also molecules that donate or accept a pair of electrons to form a coordinate covalent bond with the central metal atom of a coordination complex. (From Dorland, 27th ed)Drosophila Proteins: Proteins that originate from insect species belonging to the genus DROSOPHILA. The proteins from the most intensely studied species of Drosophila, DROSOPHILA MELANOGASTER, are the subject of much interest in the area of MORPHOGENESIS and development.Scent Glands: Exocrine glands in animals which secrete scents which either repel or attract other animals, e.g. perianal glands of skunks, anal glands of weasels, musk glands of foxes, ventral glands of wood rats, and dorsal glands of peccaries.Bees: Insect members of the superfamily Apoidea, found almost everywhere, particularly on flowers. About 3500 species occur in North America. They differ from most WASPS in that their young are fed honey and pollen rather than animal food.Oviposition: The process of laying or shedding fully developed eggs (OVA) from the female body. The term is usually used for certain INSECTS or FISHES with an organ called ovipositor where eggs are stored or deposited before expulsion from the body.Butanols: Isomeric forms and derivatives of butanol (C4H9OH).Petunia: A plant genus of the family SOLANACEAE. Members contain steroidal glycosides.Neurons, Afferent: Neurons which conduct NERVE IMPULSES to the CENTRAL NERVOUS SYSTEM.Nose: A part of the upper respiratory tract. It contains the organ of SMELL. The term includes the external nose, the nasal cavity, and the PARANASAL SINUSES.Volatile Organic Compounds: Organic compounds that have a relatively high VAPOR PRESSURE at room temperature.Elements: Substances that comprise all matter. Each element is made up of atoms that are identical in number of electrons and protons and in nuclear charge, but may differ in mass or number of neutrons.Menthol: An alcohol produced from mint oils or prepared synthetically.Imprinting (Psychology): A particular kind of learning characterized by occurrence in very early life, rapidity of acquisition, and relative insusceptibility to forgetting or extinction. Imprinted behavior includes most (or all) behavior commonly called instinctive, but imprinting is used purely descriptively.1-Butanol: A four carbon linear hydrocarbon that has a hydroxy group at position 1.Electrodiagnosis: Diagnosis of disease states by recording the spontaneous electrical activity of tissues or organs or by the response to stimulation of electrically excitable tissue.Catfishes: Common name of the order Siluriformes. This order contains many families and over 2,000 species, including venomous species. Heteropneustes and Plotosus genera have dangerous stings and are aggressive. Most species are passive stingers.Discrimination Learning: Learning that is manifested in the ability to respond differentially to various stimuli.In Situ Hybridization: A technique that localizes specific nucleic acid sequences within intact chromosomes, eukaryotic cells, or bacterial cells through the use of specific nucleic acid-labeled probes.Cyclic Nucleotide-Gated Cation Channels: A subgroup of cyclic nucleotide-regulated ION CHANNELS within the superfamily of pore-loop cation channels. They are expressed in OLFACTORY NERVE cilia and in PHOTORECEPTOR CELLS and some PLANTS.Manduca: A genus of sphinx or hawk moths of the family Sphingidae. These insects are used in molecular biology studies during all stages of their life cycle.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Water Movements: The flow of water in enviromental bodies of water such as rivers, oceans, water supplies, aquariums, etc. It includes currents, tides, and waves.Phenothiazines: Compounds containing dibenzo-1,4-thiazine. Some of them are neuroactive.Animals, Genetically Modified: ANIMALS whose GENOME has been altered by GENETIC ENGINEERING, or their offspring.