ABSTRACT
High-fat foods tend to be palatable and can cause addiction in mice via a reinforcing effect. However, mice showed preference for low fat concentrations that do not elicit a reinforcing effect in a two-bottle choice test with water as the alternative. This behavior indicates the possibility that the mechanism underlying fat palatability may differ depending on the dietary fat content. To address this issue, we examined the influences of the opioid system and olfactory and gustatory transductions on the intake and reinforcing effects of various concentrations of a dietary fat emulsion (Intralipid). We found that the intake and reinforcing effects of fat emulsion were reduced by the administration of an opioid receptor antagonist (naltrexone). Furthermore, the action of naltrexone was only observed at higher concentrations of fat emulsion. The intake and the reinforcing effects of fat emulsion were also reduced by olfactory and glossopharyngeal nerve transections (designated ONX and GLX, respectively). In contrast to naltrexone, the effects of ONX and GLX were mainly observed at lower concentrations of fat emulsion. These results imply that the opioid system seems to have a greater role in determining the palatability of high-fat foods unlike the contribution of olfactory and glossopharyngeal nerves.
Subject(s)
Dietary Fats/metabolism , Food Preferences/physiology , Naltrexone/pharmacology , Narcotic Antagonists/pharmacology , Reinforcement, Psychology , Animals , Dietary Fats/administration & dosage , Emulsions/administration & dosage , Emulsions/metabolism , Fat Emulsions, Intravenous/administration & dosage , Fat Emulsions, Intravenous/metabolism , Glossopharyngeal Nerve Injuries/chemically induced , Male , Mice , Mice, Inbred BALB C , Olfactory Nerve Injuries/chemically induced , Phospholipids/administration & dosage , Phospholipids/metabolism , Soybean Oil/administration & dosage , Soybean Oil/metabolismABSTRACT
We herein report the first case of glossopharyngeal nerve and vagus nerve palsies that appeared after an influenza vaccination. A 15-year-old boy developed dysphagia and dysarthria seven days after receiving an inoculation of the inactivated influenza vaccine. Massive intravenous immunoglobulin (IVIg) treatment was applied, as the patient's symptoms were considered to be immunological adverse effects of the influenza vaccine. He responded well to IVIg, and the symptoms immediately diminished. The mechanisms underlying the development of neurologic symptoms following vaccination are difficult to determine; however, providing immediate immunological treatment, such as IVIg, is effective and beneficial in countering these symptoms.