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Physiology
Published in Stephen W. Carmichael, Susan L. Stoddard, The Adrenal Medulla 1986 - 1988, 2017
Stephen W. Carmichael, Susan L. Stoddard
Lenz (1988) reported that injection of canine gastrin-releasing peptide into the third ventricle of conscious dogs acts centrally to activate the sympathoadrenal system. This peptide inhibits gastric emptying of a liquid meal via a vagally-mediated mechanism and increases left gastric artery blood flow by releasing adrenal medullary epinephrine. The pathways by which gastrin-releasing peptide mediates these effects remain unknown.
Brain Environment Interactions: Stress, Posttraumatic Stress Disorder, and the Need for a Postmortem Brain Collection
Published in Psychiatry, 2022
Elizabeth Osuch, Robert Ursano, He Li, Maree Webster, Chris Hough, Carol Fullerton, Gregory Leskin
Some of the early work on the role of the nervous system on behavior in response to the environment was conducted by Eric Kandel on the marine invertebrate Aplysia (snail). Using this organism, he showed that repeated stimulation with an inert (neither rewarding nor aversive) stimulus resulted in a decrease in the animal’s response to the stimulus. This was a consequence of a decrease in the synaptic effectiveness of the pathways to the motor neurons compared with when first administered (Kandel, 1991). While this may seem like a small discovery, it paved the way to understanding how humans learn to ignore extraneous and unimportant environmental stimuli—a problem for people with several mental illnesses, from attention deficit disorder and schizophrenia to PTSD. More recently, studies in rodents demonstrated a connection between the gene for a substance known as gastrin–releasing peptide (a substance usually thought of in relation to gut activity, but now found in the amygdala—a region of the brain involved with fear), and the extent to which an animal learns to fear a particular stimulus (Shumyatsky et al., 2002). These studies help to delineate the mechanisms by which environmental stimuli interact with and affect the brain at a cellular level, thereby leading to emotionally driven behaviors.
The Vagus Nerve and the Celiaco-mesenteric Ganglia Participate in the Feeding Responses Evoked by Non-sulfated Cholecystokinin-8 in Male Sprague Dawley Rats
Published in Endocrine Research, 2020
Amged I. Dafalla, Thaer R. Mhalhal, Kenneth Hiscocks, John Heath, Ayman I. Sayegh
In 1981 Smith and colleagues demonstrated that bilateral subdiaphragmatic abdominal vagotomy blocks the satiety effects by S CCK-8,7 a result which has been replicated by many laboratories including ours.8,42,43 In addition, this finding has been documented using other peptides e.g. gastrin-releasing peptide (GRP),44 peptide tyrosine45 and glucagon-like peptide-1 (GLP-1).42 The current study found a similar role for the vagus nerve in the reduction of food intake evoked by NS CCK-8. Furthermore, it is critical to mention that total subdiaphragmatic vagotomy, as done in this study, does not distinguish between the role of the efferent and the afferent arms of the vagus in reduction of food intake by NS CCK-8. Although we predict that this response, similar to S CCK-8,46 is mediated by vagal afferents, this prediction however requires further confirmation by using capsaicin-treated rats. Capsaicin is a neurotoxin which destroys the afferent, sensory, C-type fibers.
Radioactive polymeric nanoparticles for biomedical application
Published in Drug Delivery, 2020
Shentian Wu, Edward Helal-Neto, Ana Paula dos Santos Matos, Amir Jafari, Ján Kozempel, Yuri José de Albuquerque Silva, Carolina Serrano-Larrea, Severino Alves Junior, Eduardo Ricci-Junior, Frank Alexis, Ralph Santos-Oliveira
Another example for a possible theranostics system is the development of nanoparticles conjugated with arginine-glycine-aspartic acid peptide, polyethylene glycol, and croconaine dye labeled with 125I. These NPs showed preference for angiogenic tumor vessels favoring their possible theranostic use (Tang et al., 2018). Gibbens-Bandala and colleagues evaluated a paclitaxel PLGA NP conjugated with bombesin (gastrin-releasing peptide that binds to gastrin receptors overexpressed in breast cancer) labeled with 177Lu. They observed a controlled release of paclitaxel as well as a higher uptake of tumor cells suggesting an interesting system with therapeutic and diagnostic effects (Gibbens-Bandala et al., 2019). Another system described for breast cancer treatment and detection was based on magnetic NPs coated with chitosan, conjugated with a radioisotope chelator and bombesin labeled with 68Ga. It was verified that bombesin conjugated with NPs can be an interesting binder for gastrin receptor of tumor cells. Moreover, these NPs can be used in PET/MRI imaging for detection of breast, lung, and prostate cancers (Hajiramezanali et al., 2019).