Dihydroergotamine (DHE) is an acute antimigraine agent that displays affinity for dopamine D-like receptors, serotonin 5-HT receptors and α/α-adrenoceptors. Since activation of vascular α/α-adrenoceptors results in systemic vasopressor... more
Dihydroergotamine (DHE) is an acute antimigraine agent that displays affinity for dopamine D-like receptors, serotonin 5-HT receptors and α/α-adrenoceptors. Since activation of vascular α/α-adrenoceptors results in systemic vasopressor responses, the purpose of this study was to investigate the specific role of α- and α-adrenoceptors mediating DHE-induced vasopressor responses using several antagonists for these receptors. For this purpose, 135 male Wistar rats were pithed and divided into 35 control and 100 pretreated i.v. with ritanserin (100 μg/kg; to exclude the 5-HT receptor-mediated systemic vasoconstriction). Then, the vasopressor responses to i.v. DHE (1-3100 μg/kg, given cumulatively) were determined after i.v. administration of some α/α-adrenoceptor antagonists. In control animals (without ritanserin pretreatment), the vasopressor responses to DHE were: (i) unaffected after prazosin (α; 30 μg/kg); (ii) slightly, but significantly, blocked after rauwolscine (α; 300 μg/kg); ...
This study compared the cardiac sympatho-inhibitory responses produced by agonists at α -adrenergic (B-HT 933), dopamine D -like (quinpirole) and histamine H /H (immepip) receptors between normoglycemic and streptozotocin-pretreated... more
This study compared the cardiac sympatho-inhibitory responses produced by agonists at α -adrenergic (B-HT 933), dopamine D -like (quinpirole) and histamine H /H (immepip) receptors between normoglycemic and streptozotocin-pretreated (diabetic) pithed rats. Intravenous (i.v.) continuous infusions of B-HT 933, quinpirole or immepip were used in normoglycemic and diabetic pithed rats to analyse their sympatho-inhibitory effects on the electrically-stimulated cardioaccelerator sympathetic outflow. Both in normoglycemic and diabetic animals, B-HT 933 (until 100 μg/kg.min) and quinpirole (until 10 μg/kg.min) inhibited the tachycardic responses to electrical sympathetic stimulation, but not those to i.v. bolus of exogenous noradrenaline. These sympatho-inhibitory responses were more pronounced in diabetic than in normoglycemic animals. Accordingly, the areas under the curve for 100 μg/kg.min B-HT 933 and 10 μg/kg.min quinpirole in diabetic rats (1065 ± 70 and 920 ± 35, respectively) were s...
Migraine is a disabling neurovascular disorder, characterized by moderate to severe unilateral headaches, nausea, photophobia, and/or phonophobia, with a higher prevalence in women than in men, which can drastically affect the quality of... more
Migraine is a disabling neurovascular disorder, characterized by moderate to severe unilateral headaches, nausea, photophobia, and/or phonophobia, with a higher prevalence in women than in men, which can drastically affect the quality of life of migraine patients. In addition, this chronic disorder is related with metabolic comorbidities associated with the patient's lifestyle, including obesity and diabetes mellitus (DM). Beyond the personal and socioeconomic impact caused by migraine, obesity and DM, it has been suggested that these metabolic disorders seem to be related to migraine since: (i) they are a risk factor for developing cardiovascular disorders or chronic diseases; (ii) they can be influenced by genetic and environmental risk factors; and (iii) while clinical and epidemiological studies suggest that obesity is a risk factor for migraine, DM (i.e., type 1 and type 2 DM) have been reported to be either a protective or a risk factor in migraine. On this basis, and give...
Migraine is a severe neurovascular disorder of which the pathophysiology is not yet fully understood. Besides the role of inflammatory mediators that interact with the trigeminovascular system, cyclic fluctuations in sex steroid hormones... more
Migraine is a severe neurovascular disorder of which the pathophysiology is not yet fully understood. Besides the role of inflammatory mediators that interact with the trigeminovascular system, cyclic fluctuations in sex steroid hormones are involved in the sex dimorphism of migraine attacks. In addition, the pituitary-derived hormone prolactin and the hypothalamic neuropeptide oxytocin have been reported to play a modulating role in migraine and contribute to its sex-dependent differences. The current narrative review explores the relationship between these two hormones and the pathophysiology of migraine. We describe the physiological role of prolactin and oxytocin, its relationship to migraine and pain, and potential therapies targeting these hormones or their receptors.In summary, oxytocin and prolactin are involved in nociception in opposite ways. Both operate at peripheral and central levels, however, prolactin has a pronociceptive effect, while oxytocin appears to have an ant...
It has been reported that metformin reduces blood pressure although the mechanisms have not been described. Indeed, several mechanisms could be implicated including the interaction with α-adrenoceptors or inhibition of sympathetic... more
It has been reported that metformin reduces blood pressure although the mechanisms have not been described. Indeed, several mechanisms could be implicated including the interaction with α-adrenoceptors or inhibition of sympathetic outflow. Therefore, this study was designed to determine the capability of metformin to block the vasopressor responses induced by α1/2-adrenoceptor agonists or selective electrical stimulation of sympathetic outflow. For this purpose, Wistar male rats were anesthetized, pithed and cannulated for selective preganglionic stimulation of the vasopressor sympathetic outflow or drugs administration. The effect of i.v. bolus injection of metformin (180 and 310mg/kg) or its vehicle (bidistilled water) was studied on the vasopressor responses induced by: (1) selective sympathetic stimulation (0.03-3Hz); (2) exogenous noradrenaline (0.03-3μg/kg); (3) methoxamine (1-100μg/kg); and (4) UK 14,304 (0.1-30μg/kg). The tachycardic responses to noradrenaline were also inve...
One of the problems associated to bacterial biofilms is the extraordinary resistance to biocides and antibiotics. The biofilm formation gives advantages to bacteria as the natural protection from the environment and the host defense... more
One of the problems associated to bacterial biofilms is the extraordinary resistance to biocides and antibiotics. The biofilm formation gives advantages to bacteria as the natural protection from the environment and the host defense mechanisms. It has been reported that the bacteria are forming biofilm adhered to the walls of water pipes. The bacterial biofilm formation in the water pipes has been of interest in many countries because are pathogenic microorganisms for what constitutes a threat to public health. The present study aimed to seek the antibiotic resistance by bacteria to form biofilm into water pipes commonly used.
Hippocampal high frequency electrical stimulation (HFS) at 130 Hz has been proposed as a therapeutical strategy to control neurological disorders such as intractable temporal lobe epilepsy (TLE). This study was carried out to determine... more
Hippocampal high frequency electrical stimulation (HFS) at 130 Hz has been proposed as a therapeutical strategy to control neurological disorders such as intractable temporal lobe epilepsy (TLE). This study was carried out to determine the effects of hippocampal HFS on the memory process and the probable involvement of amino acids. Using the autoshaping task, we found that animals receiving hippocampal HFS showed augmented short-term, but not long-term memory formation, an effect blocked by bicuculline pretreatment and associated with enhanced tissue levels of amino acids in hippocampus. In addition, microdialysis experiments revealed high extracellular levels of glutamate, aspartate, glycine, taurine, and alanine during the application of hippocampal HFS. In contrast, GABA release augmented during HFS and remained elevated for more than 1 h after the stimulation was ended. HFS had minimal effects on glutamine release. The present results suggest that HFS has an activating effect on specific amino acids in normal hippocampus that may be involved in the enhanced short-term memory formation. These data further provide experimental support for the concept that hippocampus may be a promising target for focal stimulation to treat intractable seizures in humans.
