We studied the effects of atipamezole, an alpha 2-adrenoceptor antagonist, on hypnosis induced by medetomidine, an alpha 2-adrenoceptor agonist (1 mg/kg IP), and pentobarbital (40 mg/kg IP) by testing the righting reflex in the rat. The duration of antinociception was assessed with repeated pinch tests. Medetomidine-induced hypnosis and antinociception were inhibited by atipamezole at doses greater than 0.1 mg/kg. Atipamezole restored the righting reflex at a dose ratio that was 1:10 or more to that of medetomidine used to induce hypnosis.
Joint manipulation has long been used for pain relief. However, the underlying mechanisms for manipulation-related pain relief remain largely unexplored. The purpose of the current study was to determine which spinal neurotransmitter receptors mediate manipulation-induced antihyperalgesia. Rats were injected with capsaicin (50 microl, 0.2%) into one ankle joint and mechanical withdrawal threshold measured before and after injection. The mechanical withdrawal threshold decreases 2 h after capsaicin injection.
The Journal of Pharmacology and Experimental Therapeutics
Ephedra species of plants have both beneficial and adverse effects primarily associated with the presence of ephedrine alkaloids. Few reports have appeared that examine the direct actions of ephedrine alkaloids on human subtypes of adrenergic receptors (ARs). In the present study, ephedrine alkaloids were evaluated for their binding affinities on human alpha(1A)-, alpha(1B)-, alpha(1D)-, alpha(2A)-, alpha(2B)-, and alpha(2C)-AR subtypes expressed in HEK and Chinese hamster ovary cells.
In a previous study, we showed that electroacupuncture (EA) applied to the SI-6 point on the contralateral forelimb produces long-lasting and powerful analgesia in pain caused by ankle sprain in a rat model. To investigate the underlying mechanism of EA analgesia, the present study tested the effects of various antagonists on known endogenous analgesic systems in this model. Ankle sprain was induced in anesthetized rats by overextending their right ankle with repeated forceful plantar flexion and inversion of the foot.
Labetalol, a combined alpha1, beta1, and beta2 adrenoceptor-blocking drug, has been shown to have analgesic properties in vivo. To determine the underlying mechanisms, we examined its effects on GABAA receptor-mediated spontaneous inhibitory postsynaptic currents (sIPSCs) and spontaneous firings of rat ventrolateral periaqueductal gray (PAG) neurons, either mechanically dissociated, or in acute brain slices. These PAG neurons mediate opioid-mediated analgesia and pain transmission and are under tonic control of GABAergic interneurons.
Central sensitization, caused either by tissue inflammation or peripheral nerve injury, plays an important role in persistent pain. An animal model of capsaicin-induced pain has well-defined peripheral and central sensitization components, thus is useful for studying the analgesic effect on two separate components. The focus of this study is to examine the analgesic effects of electroacupuncture (EA) on capsaicin-induced secondary hyperalgesia, which represents central sensitization.
We describe 5 men with urinary retention and indwelling urethral catheters who were treated with repetitive prostatic massage, antimicrobials, alpha blockers, and--in 2 cases--finasteride. We retrospectively reviewed the charts of all patients presenting to the genitourinary clinic with indwelling urinary catheters during a 1-year period. Five men (mean age, 70 years; range, 64-76; SD 4.47) presented to the Manila Genitourinary Clinic (Cebu Branch), Cebu, Philippines, wearing indwelling urinary catheters placed for acute urinary retention.
The efficacy of tamsulosin in the treatment of chronic non-bacterial prostatitis was evaluated in a randomized clinical observation of 105 male outpatients conducted for 90 days. Patients were randomly divided into five groups (n = 21 per group) according to prostatitis type IIIA or IIIB and therapy regimens (tamsulosin, levofloxacin, or tamsulosin plus levofloxacin combination therapy).
To explore the pathophysiological role of leptin in obesity-related hypertension, we examined cardiovascular phenotypes of transgenic skinny mice whose elevated plasma leptin concentrations are comparable to those seen in obese subjects. We also studied genetically obese KKA(y) mice with hyperleptinemia, in which hypothalamic melanocortin system is antagonized by ectopic expression of the agouti protein. Systolic blood pressure (BP) and urinary catecholamine excretion are elevated in transgenic skinny mice relative to nontransgenic littermates.
American Journal of Physiology. Heart and Circulatory Physiology
Ischemic preconditioning (PC) has been proposed as an endogenous form of protection against-ischemia reperfusion injury. We have shown that PC does not prevent postischemic dysfunction in the aging heart. This phenomenon could be due to the reduction of cardiac norepinephrine release, and it has also been previously demonstrated that age-related decrease of norepinephrine release from cardiac adrenergic nerves may be restored by caloric restriction.