جستجوی مقالات مرتبط با کلیدواژه « گیرنده های بتا » در نشریات گروه « پزشکی »

Thyroid nodules are common. 4-7% of adults have a palpable nodule and up to 50-70% of nodules are detected in high-resolution sonography. Thyroid nodules in women are 4 times greater than men and the rate of thyroid cancer in women is 3:1 compared to men, and is the sixth most common cancer in women. Epidemiological findings and experimental evidences show that sex hormones, especially estrogen, may have effect on this gland and its neoplasm. The aim of this study was to investigate the association between rs1256049 polymorphism in the estrogen receptor beta gene with thyroid nodular disease. In this case-control study, 146 Patients with nodular thyroid and 151 health individuals were referred to Amiralmomenin hospital of Arak were recruited in study. Diagnosis is based on by ultrasonography and was confirmed by an endocrinologist. Genomic DNA was extracted from EDTA treated whole blood. The genotypes were determined using tetra-amplification refractory mutation system-polymerase chain reaction (T-ARMS-PCR) and analyzed by statistical methods. The frequency of CC, TC and TT genotypes in case group 136(93.2%), 10(6.8%) and 0(0%) and in the control group 139(92.1%), 12(7.9%) and 0(0%) were obtained respectively. No statistically significant association (p=0.72) was observed between nodular thyroid disease and rs1256049 polymorphism. Our findings showed no significant association between rs1256049 polymorphism and nodular thyroid disease. For best deduction, it is recommended that this study be done in other populations.

Central beta-noradrenergic system plays an important role in the learning and memory processes. Dorsal hippocampus also has an overlapped distribution of beta-noradrenergic receptors. The aim of this study was to evaluate the possible role of the dorsal hippocampal beta-1 noradrenergic receptors in memory retrieval using a passive avoidance learning task. This experimental study was performed on adult male Wistar rats (weight، 230±20gr). After anaesthetizing، the rats were cannulated into dorsal hippocampus using the stereotaxic surgery. After one week، passive avoidance memory was studied in two phases: training and testing with a 24h interval. The step-through latency to enter dark compartment and the time spent in this compartment was recorded for the evaluation of memory. All animals received drugs or saline، as intra- dorsal hippocampal microinjection، 30 min before testing. Pre-testing administration of dobutamine (1 μg/rat)، a beta-1 noradrenergic receptor agonist، potentiated passive avoidance memory retrieval، while pre-testing injection of betaxolol (0. 5μg/rat)، a beta-1 noradrenergic receptor antagonist، inhibited passive avoidance memory retrieval. Also، the injection of ineffective and low doses of betaxolol (0. 125 and 0. 25 μg/rat) inhibited the effect of dobutamine on the memory retrieval. It seems that beta-1 noradrenergic receptors of the dorsal hippocampus may mediate memory retrieval in a passive avoidance learning model.

Beta-2 adrenoceptors in blood vessels are one of the active factors that play a role in regulation of tissue blood flow. in diabetic angiopathy, responsiveness of these receptors is decreased, while that is increased in inflammation. According to these opposite effects, the aim of this study was to investigate the vasodilatory response of knee joint blood vessels to salbutamol (Beta-2 adrenoceptor agonist) in IDDM with combination of acute inflammation. Acute knee joint inflammation was induced by intraarticular injection of kaolin 4% and induction of diabetes was performed by streptozotocine (55 mg/kg). Wistar rats weighting 200-300 gr were used. The animals divided in 5 groups as: the control, saline, diabetic, inflammatory and diabetic- inflammatory. Blood flow of knee joint was measured using Laser Doppler Flowmeter Technique (LDF). Vasodilatation of articular micro vascular was measured in response to topical application of different concentration (10 -11 -10 -1) of salbutamol. Results obtained in this study showed that: 1- Increased knee joint diameter and perimeter due to acute inflammation in diabetic rat knee joint were significantly lesser than that of inflammatory rats. 2- Responsiveness of Beta-2 adrenoceptors were increased in kaolin- induced acute inflammation. 3- In diabetic rats, kaolin- induced acute inflammation could not increase the responsiveness of Beta-2 adrenoceptors. Based on above mentioned results, we conclude that diabetes inhibits the increasing effects of acute inflammation on responsiveness of Beta-2 adrenoceptors.

The aim of this study was to investigate the effect of ~2- adrenoceptors activation on the rat knee joint blood flow changes in acute inflammation. The acute inflammation was induced by intra articular injection of carrageenan (%3) and kaoline (3%) on the rat knee joint. The change of blood flow in response to salbutamol (2- adrenoceptor agonist) in experimental and control groups was studied over a 5.5 hour period, using the Laser Doppler Flowmetery (LDF) technique. Unilateral injection of carrageenan and kaoline (0.1ml) into the right knee joint, increased the diameter of the injected knee at 1, 2, 3, 4 and 5 hours post-injection with the maximum response at the 4.Sth hour. In control animals, topical application of 10,11, 10-9, 10'7 and 10'3 M salbutamol onto the exposed joint capsule increased the blood flow. But the dose of 10'7 M was more reliable than the other doses. Unilateral injection of carrageenan and kaoline increased the response to salbutamol in both of the ipsilateral and contralateral knees of the experimental animals as compared to the control (22.38±2.88%, 36.38±3.88%, respectively, p<0.01). To avoid the influence of 1 and cc-adrenoceptors, 15 min before the salbutamol application, atenolol (1-antagonist, lmg/kg i.p.) and phenoxybenzamine (-antagonist, 10 mg/kg i.p.) were injected. Neither the phenoxybenzamine nor the atenolol had any significant effect on the contralateral knee blood flow in the both control and inflammatory groups: But the salbutamol with the presence of these two antagonists increased the blood flow significantly. Discussion and These findings indicated that the vasodilator response to salbutamol is increased in the acute inflammation. The local application of salbutamol in the presence of propranolol (1 and 2 - antagonist) causes a significant reduction in the joint blood flow. Based on the results, it could be concluded that the activation of 2-adrenoceptors may cause the blood flow to ncrease. The mechanisms responsible for this increase remains to be investigated.

The development of radioligand - binding studies has greatly advanced our knowledge of the molecular pharmacology of beta - adrenoceptors. Using this technique it became possible for the first time to directly determine the tissue concentration of beta - adrenoceptors, and by this, the responsiveness of tissues to beta - adrenergic stimulation. One major insight into the molecular pharmacology of beta - adrenoceptors to come from radioligand - binding studies was that the tissue concentration of beta - adrenergic is not a fixed number, but is rather dynamically regulated by a variety of drugs, hormones, physiological and pathologic conditions.
In addition to the changes that occur in receptor characteristics, post - receptor events may be influenced by different pathologic states which in turn affect beta - adrenoceptor responsiveness.