In order to investigate the dynamic processes of mRNA levels of proenkephalin, proopiomelanocortin, prodynorphin, and opioid receptors (δ-, μ-, and κ-receptor) induced by electroacupuncture (EA) in the central nerve system, goats were stimulated by EA of 60 Hz for 0.5 h at a set of Baihui, Santai, Ergen, and Sanyangluo points. The pain threshold was measured using the method of potassium iontophoresis. The mRNA levels of the three opioid peptide precursors and three opioid receptors were determined with quantitative real-time PCR and the levels of Met-enkephalin with SABC immunohistochemistry at 0.5 h before and at 0, 2, 4, 6, 8, 12, and 24 h after EA. The results showed that the pain threshold correlated (P < 0.01) with Met-enkephalin immunoactivities in the measured nuclei and areas of goats. The analgesic aftereffect lasted for 12 h at least. The mRNA levels of the three opioid peptide precursors and three opioid receptors began to increase at 0 h, reached the peak during the time from 4 h to 6 h or at 12 h, and remained higher at 24 h after EA was discontinued. These results suggested that the initiation of gene expression of opioid peptides and the three receptors may be associated with EA-induced analgesic aftereffect.

Electroacupuncture in combination with a low dose of dexmedetomidine (5 μg/kg, IM) administered to goats provided antinociception.

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SummaryIn recent years, alpha 2 agonists are the most widely used as sedative and analgesic drugs in veterinary medicine because of several useful properties like fast onset, reversibility and analgesia. Alpha 2 agonists produce different actions by binding to their corresponding receptor subtypes located on various parts of the central nervous system. Ruminants are especially sensitive to alpha 2 agonists due to the distribution of the specific alpha 2 adrenoceptor subtypes, compared with other species. In ruminants, alpha 2 agonists are generally used as sedatives and analgesics for restraint, clinical diagnosis, and minor surgeries. Clinical experiments indicated that analgesia does not exist throughout the period of sedation, so these agents alone are not sufficient for painful or major surgical procedure. Epidural administration of alpha 2 agonists produced potent analgesia with minimal sedative or cardiovascular effects, and considered one of the most reliable techniques in ruminant. Alpha 2 agonists also used as a preanesthetic medication and have been obviously anesthetic sparing effects. They causes some unwanted effects, such as excessive saliva, bradycardia, depressed respiratory rate, decreased rectal temperature, hyperglycemia, uterine contractions and decreased ruminal and intestinal motility. These side effects are influenced by the doses and administration routes of alpha 2 agonists, and their selectivity to alpha 2 adrenoceptor subtypes. Attentions should be taken to avoid the use of these agents in sick patients, while careful monitoring of the patient condition is always mandatory after receiving these agents. Fortunately, the availability of specific antagonists assures the uses of alpha 2 agonists in ruminants. For the safety, an appropriate low dose of alpha 2 agonists is always recommended in ruminants. Keywords ÖzetSon yıllarda alfa 2 antagonistleri çabuk etki, geridönüşebilirlilik ve analji gibi bazı özellikleri nedeniyle veteriner hekimlikte sedatif ve analjezik olarak en yaygın kullanılan ilaçlardır. Alfa 2 antagonistleri merkezi sinir sisteminin çeşitli bölgelerinde yer alan ilişkili reseptörlere bağlanmak suretiyle değişik reaksiyonlara neden olur. Ruminantlar diğer türlerle karşılaştırıldığında spesifik alfa 2 adenoreseptör subtipleri nedeniyle alfa 2 antagonistlerine karşı özellikle sensitiflerdir. Ruminantlarda alfa 2 antagonistleri genel olarak zapturapt, klinik tanı ve küçük cerrahiler amacıyla sedatif ve analjezik olarak kullanılır. Klinik deneyler analjezinin sedasyonun süresinin tümü boyunca mevcut olmadığını göstermektedir. Bu nedenle bu maddeler acılı veya büyük cerrahi müdahalelerde tek başlarına yeterli değillerdir. Alfa 2 antagonistlerinin epidural uygulanması minimal sedatif veya kardiyovasküler etkiler ile birlikte muhtemel analjezi üretmektedir. Bu uygulama ayrıca ruminantlarda en güvenilir teknik olarak kabul edilmektedir. Alfa 2 antagonistleri ayrıca preanastetik uygulama olarak da kullanılmaktadır ve bariz olarak anestetik ajanın az kullanımının sağlayıcı etkileri...

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