Morphine Dependence: Strong dependence, both physiological and emotional, upon morphine.Morphine: The principal alkaloid in opium and the prototype opiate analgesic and narcotic. Morphine has widespread effects in the central nervous system and on smooth muscle.Naloxone: A specific opiate antagonist that has no agonist activity. It is a competitive antagonist at mu, delta, and kappa opioid receptors.Substance Withdrawal Syndrome: Physiological and psychological symptoms associated with withdrawal from the use of a drug after prolonged administration or habituation. The concept includes withdrawal from smoking or drinking, as well as withdrawal from an administered drug.Narcotic Antagonists: Agents inhibiting the effect of narcotics on the central nervous system.Narcotics: Agents that induce NARCOSIS. Narcotics include agents that cause somnolence or induced sleep (STUPOR); natural or synthetic derivatives of OPIUM or MORPHINE or any substance that has such effects. They are potent inducers of ANALGESIA and OPIOID-RELATED DISORDERS.Matricaria: A plant genus of the family ASTERACEAE. M. chamomilla appears similar to Anthemis but this flower disk is conical and hollow and lacks chaffy bract scales and the odor is weaker. The common name of 'manzanilla' is confused with other meanings of the word. 'Matricaria chamomilla sensu' is classified by some as Tripleurospermum perforata. Other plants with similar common names include CHAMAEMELUM; TRIPLEUROSPERMUM and ANTHEMIS.Drug Tolerance: Progressive diminution of the susceptibility of a human or animal to the effects of a drug, resulting from its continued administration. It should be differentiated from DRUG RESISTANCE wherein an organism, disease, or tissue fails to respond to the intended effectiveness of a chemical or drug. It should also be differentiated from MAXIMUM TOLERATED DOSE and NO-OBSERVED-ADVERSE-EFFECT LEVEL.Receptors, Opioid, mu: A class of opioid receptors recognized by its pharmacological profile. Mu opioid receptors bind, in decreasing order of affinity, endorphins, dynorphins, met-enkephalin, and leu-enkephalin. They have also been shown to be molecular receptors for morphine.Morphine Derivatives: Analogs or derivatives of morphine.Behavior, Animal: The observable response an animal makes to any situation.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Analgesics, Opioid: Compounds with activity like OPIATE ALKALOIDS, acting at OPIOID RECEPTORS. Properties include induction of ANALGESIA or NARCOSIS.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Biological Products: Complex pharmaceutical substances, preparations, or matter derived from organisms usually obtained by biological methods or assay.Access to Information: Individual's rights to obtain and use information collected or generated by others.Health Resources: Available manpower, facilities, revenue, equipment, and supplies to produce requisite health care and services.National Institute on Drug Abuse (U.S.): Component of the NATIONAL INSTITUTES OF HEALTH. It supports a comprehensive research portfolio that focuses on the biological, social, behavioral and neuroscientific bases of drug abuse on the body and brain as well as its causes, prevention, and treatment. NIDA, NIAAA, and NIMH were created as coequal institutes within the Alcohol, Drug Abuse and Mental Health Administration in 1974. It was established within the NATIONAL INSTITUTES OF HEALTH in 1992.United States Substance Abuse and Mental Health Services Administration: An agency of the PUBLIC HEALTH SERVICE concerned with the overall planning, promoting, and administering of programs pertaining to substance abuse and mental health. It is commonly referred to by the acronym SAMHSA. On 1 October 1992, the United States Alcohol, Drug Abuse, and Mental Health Administration (ADAMHA) became SAMHSA.Substance-Related Disorders: Disorders related to substance abuse.National Institute on Aging (U.S.): Component of the NATIONAL INSTITUTES OF HEALTH. Through basic and clinical biomedical research and training, it conducts and supports research into the nature of the aging process and diseases associated with the later stages of life. The Institute was established in 1974.Buprenorphine: A derivative of the opioid alkaloid THEBAINE that is a more potent and longer lasting analgesic than MORPHINE. It appears to act as a partial agonist at mu and kappa opioid receptors and as an antagonist at delta receptors. The lack of delta-agonist activity has been suggested to account for the observation that buprenorphine tolerance may not develop with chronic use.Enkephalin, Ala(2)-MePhe(4)-Gly(5)-: An enkephalin analog that selectively binds to the MU OPIOID RECEPTOR. It is used as a model for drug permeability experiments.Naltrexone: Derivative of noroxymorphone that is the N-cyclopropylmethyl congener of NALOXONE. It is a narcotic antagonist that is effective orally, longer lasting and more potent than naloxone, and has been proposed for the treatment of heroin addiction. The FDA has approved naltrexone for the treatment of alcohol dependence.Liposomes: Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.Injections: Introduction of substances into the body using a needle and syringe.Injections, Spinal: Introduction of therapeutic agents into the spinal region using a needle and syringe.Analgesia: Methods of PAIN relief that may be used with or in place of ANALGESICS.Delayed-Action Preparations: Dosage forms of a drug that act over a period of time by controlled-release processes or technology.Infusions, Subcutaneous: The administration of liquid medication or nutrients under the skin, usually over minutes or hours.Xiphoid Bone: Also called xiphoid process, it is the smallest and most inferior triangular protrusion of the STERNUM or breastbone that extends into the center of the ribcage.Occipital Bone: Part of the back and base of the CRANIUM that encloses the FORAMEN MAGNUM.Hydronephrosis: Abnormal enlargement or swelling of a KIDNEY due to dilation of the KIDNEY CALICES and the KIDNEY PELVIS. It is often associated with obstruction of the URETER or chronic kidney diseases that prevents normal drainage of urine into the URINARY BLADDER.Abnormalities, Drug-Induced: Congenital abnormalities caused by medicinal substances or drugs of abuse given to or taken by the mother, or to which she is inadvertently exposed during the manufacture of such substances. The concept excludes abnormalities resulting from exposure to non-medicinal chemicals in the environment.Teratogens: An agent that causes the production of physical defects in the developing embryo.Pituitary Adenylate Cyclase-Activating Polypeptide: A multi-function neuropeptide that acts throughout the body by elevating intracellular cyclic AMP level via its interaction with PACAP RECEPTORS. Although first isolated from hypothalamic extracts and named for its action on the pituitary, it is widely distributed in the central and peripheral nervous systems. PACAP is important in the control of endocrine and homeostatic processes, such as secretion of pituitary and gut hormones and food intake.Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide: A family of G-protein-coupled receptors that share significant homology with GLUCAGON RECEPTORS. They bind PITUITARY ADENYLATE CYCLASE ACTIVATING POLYPEPTIDE with high affinity and trigger intracellular changes that influence the behavior of CELLS.Receptors, Pituitary Hormone: Cell surface proteins that bind pituitary hormones with high affinity and trigger intracellular changes influencing the behavior of cells. Since many pituitary hormones are also released by neurons as neurotransmitters, these receptors are also found in the nervous system.Neuropeptides: Peptides released by NEURONS as intercellular messengers. Many neuropeptides are also hormones released by non-neuronal cells.Inositol Phosphates: Phosphoric acid esters of inositol. They include mono- and polyphosphoric acid esters, with the exception of inositol hexaphosphate which is PHYTIC ACID.Type C Phospholipases: A subclass of phospholipases that hydrolyze the phosphoester bond found in the third position of GLYCEROPHOSPHOLIPIDS. Although the singular term phospholipase C specifically refers to an enzyme that catalyzes the hydrolysis of PHOSPHATIDYLCHOLINE (EC 3.1.4.3), it is commonly used in the literature to refer to broad variety of enzymes that specifically catalyze the hydrolysis of PHOSPHATIDYLINOSITOLS.Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type IGuanosine 5'-O-(3-Thiotriphosphate): Guanosine 5'-(trihydrogen diphosphate), monoanhydride with phosphorothioic acid. A stable GTP analog which enjoys a variety of physiological actions such as stimulation of guanine nucleotide-binding proteins, phosphoinositide hydrolysis, cyclic AMP accumulation, and activation of specific proto-oncogenes.Anabasine: A piperidine botanical insecticide.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Receptors, Opioid: Cell membrane proteins that bind opioids and trigger intracellular changes which influence the behavior of cells. The endogenous ligands for opioid receptors in mammals include three families of peptides, the enkephalins, endorphins, and dynorphins. The receptor classes include mu, delta, and kappa receptors. Sigma receptors bind several psychoactive substances, including certain opioids, but their endogenous ligands are not known.AlloxanDiabetes Mellitus, Experimental: Diabetes mellitus induced experimentally by administration of various diabetogenic agents or by PANCREATECTOMY.Pain: An unpleasant sensation induced by noxious stimuli which are detected by NERVE ENDINGS of NOCICEPTIVE NEURONS.Pamphlets: Printed publications usually having a format with no binding and no cover and having fewer than some set number of pages. They are often devoted to a single subject.Patient Education as Topic: The teaching or training of patients concerning their own health needs.Drug Information Services: Services providing pharmaceutic and therapeutic drug information and consultation.Lawyers: Persons whose profession is to give legal advice and assistance to clients and represent them in legal matters. (American Heritage Dictionary, 3d ed)Drug Labeling: Use of written, printed, or graphic materials upon or accompanying a drug container or wrapper. It includes contents, indications, effects, dosages, routes, methods, frequency and duration of administration, warnings, hazards, contraindications, side effects, precautions, and other relevant information.