Morphine causes all, Except
**Morphine Effects and Side Effects**
**Core Concept**
Morphine is a potent opioid analgesic that acts on the central nervous system (CNS) to produce its therapeutic effects. It binds to mu-opioid receptors in the brain, spinal cord, and other areas, leading to pain relief, sedation, and other physiological responses.
**Why the Correct Answer is Right**
Morphine's mechanism of action involves the activation of G-protein coupled receptors, specifically mu-opioid receptors (MOR). This binding causes a cascade of intracellular signaling events, leading to analgesia, miosis (pupillary constriction), and respiratory depression. The therapeutic effects of morphine, such as pain relief, are thought to be mediated by the inhibition of nociceptive transmission in the spinal cord.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because morphine does not cause **increased blood pressure**. In fact, morphine can cause hypotension due to its vasodilatory effects and decreased sympathetic tone.
**Option B:** This option is incorrect because morphine does not cause **increased histamine release**. While morphine can cause histamine release from mast cells, this effect is not a primary action of the drug.
**Option C:** This option is incorrect because morphine does not cause **increased gastric acid secretion**. Morphine can actually cause a decrease in gastric acid secretion due to its effects on the CNS and the release of inhibitory neurotransmitters.
**Clinical Pearl / High-Yield Fact**
Morphine's effects on respiration can be unpredictable, and patients should be monitored closely for signs of respiratory depression, especially when using high doses or in combination with other CNS depressants.
**Correct Answer: A. Increased blood pressure. Increased histamine release. Increased gastric acid secretion.**