Biomedical subjects

Nejat Gacar

Publications and source records attributed to Nejat Gacar.

4 recordsLinked to original sources

PubMed2006

Effect of dextromethorphan on reference memory assessed in rats by a three-panel runway task.

The effects of dextromethorphan (DM, CAS 6700-34-1), a common over-the-counter cough suppressant, on the reference memory have been investigated by a three-panel runway setup in rats. This study was designed by using a repeated acquisition procedure such as a radialarm maze task or a water maze task. DM (20-40 mg/kg i.p.) produced a significant decrease in the number of errors (pushes made on the two incorrect panels of the three panel gates at four choice points) and latency. Systemically administered scopolamine (CAS 114-49-8) (1 mg/kg i.p.) impaired the performance on both parameters. DM (40 mg/kg i.p.) was effective in reversing the reference memory deficit induced by administration of scopolamine. DM acts as a noncompetitive antagonist of the N-methyl-D-aspartate (NMDA) receptors. Our results suggest that inhibition of NMDA receptors by DM supports its potential positive properties. This finding might present an oppurtunity for the evaluation of this old antitussive drug.

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PubMed2003

Gastric smooth muscle contractility changes in the esophageal atresia rat model: an in vitro study.

PURPOSE: The aim of the study was to investigate the gastric smooth muscle reactivity in the Adriamycin-induced esophageal atresia (EA) rat model. METHODS: The fetuses were divided into 3 groups. The control group was exposed to saline. The second group was comprised of fetuses that were exposed to Adriamycin but did not have EA (Adriamycin-no-EA group). The third group was comprised of fetuses that were exposed to Adriamycin and had EA (Adriamycin-EA group). Gastric fundus strips were studied in vitro for their contractile response to receptor activation in the 3 groups. RESULTS: Contractile responses of gastric smooth muscle to carbachol and KCl were increased in the Adriamycin-EA group compared with the Adriamycin-no-EA group. Also serotonin-induced contractile response in the Adriamycin-EA group decreased compared with the Adriamycin-no-EA group. Relaxation of gastric smooth muscle strips to isoproterenol was comparably unaffected in the Adriamycin-EA and Adriamycin-no-EA groups. Likewise, no change in the response to agonist studies was observed between the control and Adriamycin-no-EA groups. The relaxant response to papaverine was not different in the 3 groups. CONCLUSIONS: This study found changes of receptor-dependent and receptor-independent contraction of the gastric fundus smooth muscle in the fetuses with EA. Therefore, impaired contractile responses may be, at least in part, a contributing factor in the abnormal gastric motility seen in EA.

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PubMed2003

Age-related smooth muscle reactivity changes in the rat bladder: an in vitro study.

An experimental study was conducted to investigate developmental changes of the rat detrusor smooth muscle (DSM) reactivity from newborn to adult period. Urinary bladders were obtained from adult (4 months old), 1-month-old and newborn (4-7 days old) male Sprague-Dawley rats. DSM reactivity of the three groups was evaluated in organ chambers. The newborn DSM strips revealed markedly increased purinoceptor- and cholinoceptor-mediated contractions (ATP, carbachol) with increased maximum response (2.98- and 8.96-fold increase for ATP, 2.90- and 4.22-fold increase for carbachol, when the newborn bladder compared with 1-month-old and adult groups, respectively) and sensitivity (1.65- and 1.29-fold increase for ATP when the newborn bladder compared with the 1-month-old and adult groups, respectively). Additionally the maximum contractile response to KCl in the bladder from the newborn was 1.65- and 8.96-fold increased compared to bladders of the 1-month-old and adult groups, respectively. However, no significant changes in the adrenoceptor-mediated relaxation (isoproterenol) of the rat DSM were observed among the groups. These results indicate that development alters the in vitro responsiveness of rat DSM. The newborn rat bladder gains some of the adult bladder properties within 1 month. These changes are likely to reflect the changing role of parasympathetic regulation in the DSM reactivity during development of the rat bladder.

Adenosine Triphosphate↗

PubMed2003

Esophagitis impairs esophageal smooth muscle reactivity in the rat model: an in vitro study.

The present study investigated how reflux-induced esophagitis affects the smooth muscle reactivity of the esophageal body. Two different esophagitis models were used: acid gastric and mixed duodenogastric reflux. All test animals apart from the controls developed gross and histologic evidence of esophagitis. Contractile (carbachol and KCI) and relaxant (isoproterenol) esophageal smooth muscle responses were significantly decreased in the presence of acid- and mixed reflux-induced esophagitis. Similar relaxant responses to serotonin and papaverine were found in the three groups. Our study demonstrated impaired esophageal smooth muscle reactivity when esophagitis was induced by acid or mixed reflux. These changes may correspond to the functional motor abnormalities of the esophagus seen in patients with reflux esophagitis.

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