161) Which of the following nervous system chemicals is considered a neurotransmitter? A) progesterone B) testosterone C) estrogen D) serotonin 162) Julia sells St. John’s wort in her health food store. Her customers purchase this item in order to relieve: A) high blood pressure. B) convulsive disorders. C) eating disorders. D) depression. 163) Marcia buys St. John’s wort at her local health food store. She may be unaware that: A) convulsive disorders are associated with this drug. B) this drug prevents the cells that release serotonin from reabsorbing excess molecules that have remained in the synaptic gap. C) high blood pressure results from overuse of this drug. D) eating disorders are associated with this drug. 164) Irene purchases St. John’s wort in order to relieve her: A) bouts with severe depression. B) abnormally high level of dopamine. C) constant desire for sweets. D) symptoms of Parkinson’s disease. 165) Many recreational drugs produce their effects by: A) causing glial cells to produce excess myelin. B) causing GABA neurons to die. C) blocking or enhancing the actions of neurotransmitters. D) blocking glial cells from producing myelin. 166) Chemical substances in the nervous system that are similar in structure and in action to opiates are: A) hormones. B) gamma-aminobutyric acids. C) endorphins. D) neurotransmitters. 167) Endorphins have effects similar to those of natural opiates, that is, they: A) heighten pain and reduce pleasure. B) reduce pain and promote pleasure. C) reduce pain but also reduce pleasure. D) flatten mood and emotional expression. 168) Endorphins have effects similar to: A) Aspirin and Tylenol. B) dopamine. C) natural opiates. D) amphetamines. 169) Endorphins act primarily by: A) causing action potentials in neurons. B) functioning as neurotransmitters. C) altering the effects of neurotransmitters. D) blocking synaptic activity. 170) According to our textbook, endorphins play a role in the: A) appetite, sexual activity, and blood pressure of individuals. B) experience of phantom limb pain. C) destruction of glial cells that normally make myelin. D) loss of brain cells responsible for the production of acetylcholine.