ABSTRACT
Temporomandibular disorders (TMD) are defined as clinical conditions that involve the masticatory muscles, temporomandibular joint (TMJ) or both. The aim of this study was to evaluate serum 17ß-oestradiol and progesterone levels in menstruating women affected by internal derangement of the TMJ. A total of 142 women (mean age 30·2 ± 6·7) who referred to medical diagnostic laboratory of Iranian Academic Centre for Education, Culture and Research (ACECR), Mashhad Branch, were enrolled during 2007 and 2008. Forty-seven individuals had disc displacement with reduction (Group IIa) according to Research Diagnostic Criteria (RDC)/TMD Axis I diagnosis. Radioimmunoassay was used for the detection of serum 17ß-oestradiol and progesterone levels in all 142 subjects. The mean progesterone level was significantly higher in control group (11·6 ± 10·4 ng mL(-1) ) compared to women with TMD (8·4 ± 6·8 ng mL(-1) , P = 0·03). No significant difference was found in two groups regarding 17ß-oestradiol level. Lower progesterone level in women with TMD can suggest the more important role of this hormone in the development of the disorder.
Subject(s)
Estradiol/blood , Progesterone/blood , Temporomandibular Joint Dysfunction Syndrome/blood , Adult , Case-Control Studies , Cross-Sectional Studies , Female , Humans , Joint Dislocations/blood , Joint Dislocations/physiopathology , Radioimmunoassay , Temporomandibular Joint/physiopathology , Temporomandibular Joint Disc/physiopathology , Temporomandibular Joint Dysfunction Syndrome/physiopathology , Young AdultABSTRACT
Serotonin modulates afferent synaptic transmission to the lateral giant neurons of crayfish, which are command neurons for escape behavior. Low concentrations, or high concentrations reached gradually, are facilitatory, whereas high concentrations reached rapidly are inhibitory. The modulatory effects rapidly reverse after brief periods of application, whereas longer periods of application are followed by facilitation that persists for hours. These effects of serotonin can be reproduced by models that involve multiple interacting intracellular signaling systems that are each stimulated by serotonin. The dependence of the neuromodulatory effect on dose, rate, and duration of modulator application may be relevant to understanding the effects of natural neuromodulation on behavior and cognition and to the design of drug therapies.
Subject(s)
Escape Reaction/drug effects , Escape Reaction/physiology , Neurons/drug effects , Neurons/physiology , Serotonin/administration & dosage , Animals , Astacoidea , Dose-Response Relationship, Drug , Drug Administration Routes , Drug Administration Schedule , Electric Stimulation , Excitatory Postsynaptic Potentials/drug effects , Excitatory Postsynaptic Potentials/physiology , Ganglia, Invertebrate/physiology , Membrane Potentials/drug effects , Membrane Potentials/physiology , Models, Neurological , Neural Inhibition/drug effects , Neural Inhibition/physiology , Sensory Thresholds/physiology , Serotonin/metabolism , Signal Processing, Computer-Assisted , Signal Transduction/drug effects , Signal Transduction/physiology , Social IsolationABSTRACT
The excitability of the lateral giant escape reflex of socially dominant and submissive crayfish at rest and during agonistic encounters was studied and compared. During agonistic encounters the excitability of the lateral giant reflex falls, substantially in subordinates and slightly in dominants, whereas at rest excitability seems to be independent of social status. Thus, paradoxically, socially dominant animals are more likely to execute lateral giant escape reactions during interactions than are subordinates. It is suggested that subordinates under threat of attack tend to engage circuitry involved in flexible, nonreflex ("voluntary") types of escape not mediated by giant neurons and therefore inhibit giant neuron-mediated reflex circuitry that produces prompt, but less adaptive, responses. In contrast, dominants go about their business, mainly ignoring their conspecifics and relying on reflex escape to protect them from unexpected attack. Consistent with this view, escape of subordinates during agonistic encounters is mediated by nongiant, not reflex, circuitry. These observations and their interpretation suggest a possible functional role for recently described social status-dependent serotonergic modulation of the lateral giant reflex, which is inhibitory in sign in subordinates and facilitatory in dominants.
