• Molecules and Cells
• /
• v.42 no.1
• /
• pp.28-35
• /
• 2019

Animals need to be able to alter their developmental and behavioral programs in response to changing environmental conditions. This developmental and behavioral plasticity is mainly mediated by changes in gene expression. The knowledge of the mechanisms by which environmental signals are transduced and integrated to modulate changes in sensory gene expression is limited. Exposure to ascaroside pheromone has been reported to alter the expression of a subset of putative G protein-coupled chemosensory receptor genes in the ASI chemosensory neurons of C. elegans (Kim et al., 2009; Nolan et al., 2002; Peckol et al., 1999). Here we show that ascaroside pheromone reversibly represses expression of the str-3 chemoreceptor gene in the ASI neurons. Repression of str-3 expression can be initiated only at the L1 stage, but expression is restored upon removal of ascarosides at any developmental stage. Pheromone receptors including SRBC-64/66 and SRG-36/37 are required for str-3 repression. Moreover, pheromone-mediated str-3 repression is mediated by FLP-18 neuropeptide signaling via the NPR-1 neuropeptide receptor. These results suggest that environmental signals regulate chemosensory gene expression together with internal neuropeptide signals which, in turn, modulate behavior.

• The Microorganisms and Industry
• /
• v.12 no.2
• /
• pp.14-18
• /
• 1986

Barcterial chemotaxis is a transient response of an organism in a situation where environmental homogeneity has been disturbed by certain chemical compounds. The phenomenon has been described in motile bacterial species including enteric bacteria, Gram-positives(14), Spirochaetes (6) and even Archaebacteria (8). However, most comprehensive studies have been done with Escherichia coli and Salmonella typhimurium. Two analogies to higher eucaryotic sensory phenomena are provided by the study of bacterial chemotaxis. First, bacterial chemotaxis is similar to the stimulus-response of neuronal, immune and sperm cells. Second, studies of individual components involved in the bacterial sensory pathway can contribute to the understanding of the function of receptors, controling signals and molecular comparators in transmembrane signalling system. The bacterial sensory transducer, a chemoreceptor in a broad sense, is a unique entity for studying sensory function in which sensory reception, signalling and adaptation are integrated (7,18).

• Genomics & Informatics
• /
• v.7 no.2
• /
• pp.111-121
• /
• 2009

Cell membrane proteins play crucial roles in the cell's molecular interaction with its environment and within itself. They consist of membrane-bound proteins and many types of transmembrane (TM) proteins such as receptors, transporters, channel proteins, and enzymes. Membrane proteomes of cellular organisms reveal some characteristics in their global topological distribution according to their evolutionary positions, and show their own information transfer complexity. Predicted transmembrane segments (TMSs) in membrane proteomes with HMMTOP showed near power-law distribution and frequency characteristics in 6-TMS and 7-TMS proteins in prokaryotes and eukaryotes, respectively. This reaffirms the important roles of membrane receptors in cellular communication and biological evolutionary history.

• Korean Journal of Otorhinolaryngology-Head and Neck Surgery
• /
• v.61 no.11
• /
• pp.567-572
• /
• 2018

The sensory function of the trigeminal nerve is to provide tactile, proprioceptive, and nociceptive afference by chemical stimulation. Various physical responses of the trigeminal nerve to stimuli help to defend against harmful substances. Recently, many studies have been conducted on solitary chemoreceptor cells innervated by trigeminal nerve. Most volatile organic compounds stimulate both the olfactory and trigeminal nervous systems. In general, the trigeminal nervous system is less sensitive than the olfactory nervous system. Studies have shown that sensation of the trigeminal nerve by chemical stimulation results in inhibition of olfaction. This indicates that the olfactory and trigeminal nerves interact with each other in the central nervous system. It is important to study various noxious stimuli acting on the trigeminal nerve in modern society where environmental concerns are intensifying.

• The Korean Journal of Pain
• /
• v.14 no.1
• /
• pp.46-50
• /
• 2001

Background: Ondansetron is both a central and peripheral serotonin (5HT) receptor antagonist and droperidol is a dopaminergic blocking drug which acts centrally at the chemoreceptor trigger zone. We assessed the efficacy and adverse effects of ondansetron, droperidol or both, in the prevention of postoperative emesis during postoperative intravenous patient-controlled analgesia (PCA) using butorphanol and ketorolac medication. Methods: We studied 60 women, aged 25-60 yrs, who underwent total abdominal hysterectomy (TAH), under general anesthesia using $N_2O-O_2$-enflurane. A bolus dose of 1 mg of butorphanol and 4 mg of ondansetron were given to patients and thereafter, PCA was started using 10 mg of butorphanol and 240 mg of ketorolac mixed into the 5% D/W solution (total volume; 100 ml, 1 ml of bolus dose, and 10 min of lockout interval). We also added ondansetron 4 mg (Group O, n = 20), ondansetron 4 mg and droperidol 2.5 mg (Group OD, n = 20), or droperidol 2.5 mg (Group D, n = 20) to the PCA drug. The severity of pain, nausea, vomiting, sedation and other side effects were assessed at 0, 1, 2, 6, 12, 24, 36 and 48 hr after awakening. Results: There was no difference in the incidence of nausea and vomiting between the three group [Group O: 4 (20%) and 3 (15%), respectively; Group OD: 1 (5%) and 1 (5%), respectively; Group D: 3 (15%) and 3 (15%), respectively]. Group O showed a lower sedation score than the other groups (P < 0.05). The pain score and other side effects did not show any difference between the groups. Conclusions: The combination of ondansetron and droperidol showed no clinical benefit compared with ondansetron or droperidol alone for prevention of postoperative nausea and vomiting during postoperative PCA using butorphanol and ketorolac.

• Clinical and Experimental Pediatrics
• /
• v.49 no.4
• /
• pp.446-450
• /
• 2006

Congenital central hypoventilation syndrome (CCHS) or Ondine's curse is a very rare sleep disorder that is the result of a congenital failure of the autonomic control of ventilation caused by insensitivity of the chemoreceptor to hypercapnea during sleep. Gastrointestinal motility disorders, particularly a congenital megacolon (Hirschsprung disease) is often combined with CCHS. This combination can be explained by a defect in the migration of neuronal cells from the neural crest (neurocristopathy) during the intrauterine period. A diagnosis of CCHS is made by confirming the failure of adequate ventilation in response to hypercapnea and hypoxia during sleep and the exclusion of other diseases. Young infants frequently show atypical clinical courses, and their conditions are frequently complicated with the long-term sequela of hypoxemic episodes. Therefore, a high index of suspicion and active treatment with mechanical ventilation are important for reducing recurrent hypoxemic episodes in the neonatal period. This paper reports the follow up of a case of CCHS in a neonate who showed frequent intractable apnea and cyanosis and was given artificial mechanical ventilation during sleep.

• Korean Journal of Veterinary Research
• /
• v.28 no.1
• /
• pp.145-154
• /
• 1988

Ixodes signatus nymphs were subjected to the scanning electron microscopy for the observation of the major physiological sense organs including the Hailer's organ. Finger prints and variable sensory setae were found on the body surface, and especially well developed setae were identified on the article IV and on the anal lobes. A central button-like organelle and numerous small holes were found in the spiracular plate. The Haller's organ was identified at the distal point of the tarsus I and regarded as the major sensory organ, chemoreceptor. Tow types of sensory setae were observed, the shorter ones in front of the organ and the longer ones in distal front as well as near behind of the organ. The fully opened organ was ellipsoidal and a total of seven basiconic sensory pegs rooted deeply and shaped as well arranged hook-like was found inside the organ.