NSCI 110 1st Edition Lecture 15 Outline of Last Lecture I Pharmacokinetics involves the movement of drugs throughout the body a Various means drugs are absorbed into the blood and brain b Distribution of drugs are limited i Certain molecules cannot pass through the blood brain barrier c A drug may be broken down into its components or stored in certain somatic cells d There are various means of elimination II Psychoactive drugs directly target the nervous system a May target synapses post synaptic receptors reuptake mechanisms transmitter synthesis rates III Drug responses are mediated by various means a Potency b Efficacy c Variability d Effective concentrations dosages e Tolerance Outline of Current Lecture I Drugs effects may sum if absorbed by the body at the same time a Produce IPSPs or EPSPs II Dependency sensitization learning and other variables such as basal metabolic rate and sex alter a drug s effects on an individual III A neurohormone is any hormone produced and released by neuroendocrine neurosecretory cells into the blood a A feedback system referred to as the HPA axis is responsible for the stress response and includes a fast and slow acting pathway Current Lecture Pharmacokinetics determining the date of substances administered externally to a living organism Tolerance is a reduced response to repeated exposure to a drug dose o Opioid analgesics morphine codeine heroin endomorphins enkephlins dynorphins o Cross tolerance barbiturates and alcohol GABA channels that are selective for chloride ions Also contains receptors for ethanol barbiturates neurosteroids Reduces the effectiveness of each other once exposed These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute Some factors that alter drug effects o Drug interactions Taking multiple drugs may drastically increase the magnitude of the effect by inducing EPSPs and IPSPs o Dependency requiring a drug to maintain a normal response Absence of the results in abstinence syndrome withdrawal Physiological heroin Psychological Combination o Sensitization increased responsiveness intensity type to repeated exposure to a drug dose Increased receptor density upregulation binding affinity Drug interactions o Learning unexpected vs expected effects Monkeys and amphetamine Drink fruit punch which activates sympathetic nervous system but they learn nothing harmful occurs Second effect causes activity to be lower than baseline level Placebo effect o Subject variables Age Environment Sex Body weight Basal metabolic rate Neurohormones o A hormone is a chemical released by endocrine glands into the bloodstream to affect an organ at a distance A neurohormone is any hormone produced and released by neuroendocrine neurosecretory cells into the blood o Hypothalamus produces neurohormones that enter the anterior pituitary gland through veins and the posterior pituitary through axons in response to stimuli Through instructions from these released hormones the pituitary sends hormones into the bloodstream to target endocrine glands Endocrine glands release their own hormones that stimulate target organs including the brain This feedback system is known as the hypothalamus pituitary adrenal HPA axis o Steroid hormones testosterone cortisol Synthesized from cholesterol and lipids Easily crosses cell membranes Often target DNA o Peptide hormones insulin growth hormones Peptides made from DNA Bind to receptors usually second messenger systems The HPA axis includes two pathways o Fast acting pathway Hypothalamus sends message through the spinal cord Sympathetic division is activated to stimulate the medulla of the adrenal gland The adrenal medulla releases epinephrine into the circulatory system Epinephrine activates the body s cells endocrine glands and the brain o Slow acting pathway mechanism for managing long term stress Hypothalamus releases CRH corticotropin releasing hormone into the pituitary gland The pituitary gland releases ACTH adrenocorticotropic hormone which acts on the cortex of the adrenal gland The adrenal cortex releases cortisol into the circulatory system Cortisol activates the body s cells endocrine glands and the brain o Homeostatic hormones maintain internal balance and regulate physiological systems Antidiuretic hormone o Gonadal hormones control reproduction Estrogen testosterone o Glucocorticoids are involved in stress response Cortisol corticosterone Parvocellular neurosecretory cells and anterior pituitary
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