SpasmMuscle RelaxationMusclesMuscle, SmoothMuscle SpasticityNeck MusclesMuscle ProteinsMuscle, Smooth, VascularMuscle, SkeletalMuscle ContractionSpasms, InfantileMuscle Fibers, SkeletalCervical AtlasOccipital BoneMuscle DevelopmentNeuromuscular AgentsElectromyographySpinal Cord InjuriesMuscle FatigueMotor NeuronsHemifacial SpasmBotulinum Toxins, Type ARelaxation TherapyMuscle Fibers, Fast-TwitchMuscle DenervationMuscle Fibers, Slow-TwitchMyocytes, Smooth MuscleMitochondria, MuscleOculomotor MusclesFacial MusclesMuscle, StriatedMuscle SpindlesPapillary MusclesRespiratory MusclesMuscle WeaknessCoronary VasospasmIsometric ContractionAbdominal MusclesTracheaMuscle CellsQuadriceps MuscleElectric StimulationNitric OxideVasodilationMasseter MuscleAcetylcholineMasticatory MusclesRabbitsEsophageal Spasm, DiffuseCalciumIntercostal MusclesMuscular AtrophyCyclic GMPSatellite Cells, Skeletal MuscleTime FactorsPectoralis MusclesGuinea PigsVasodilator AgentsDeuteroporphyrinsRats, Sprague-DawleyMuscular DiseasesDose-Response Relationship, DrugNitroprussideNeuromuscular JunctionNeuromuscular BlockadeHSP20 Heat-Shock ProteinsBiomechanical PhenomenaPsoas MusclesMyofibrilsMuscle Relaxants, CentralNeuromuscular Nondepolarizing AgentsRats, WistarTemporal MuscleEndothelium, VascularPenisHindlimbAortaCells, CulturedRelaxationAorta, ThoracicErgonovinePharyngeal MusclesMuscle TonusMyosin Heavy ChainsDiaphragmRNA, MessengerDogsIsoproterenolMembrane PotentialsOpossumsNitroarginineNitric Oxide DonorsCyclic GMP-Dependent Protein KinasesEnzyme InhibitorsAngina Pectoris, VariantVasoconstrictionOxadiazolesNitric Oxide SynthaseNitroglycerinKinetics