SpasmMuscle RelaxationMuscle SpasticityMusclesNeck MusclesMuscle, SmoothSpasms, InfantileCervical AtlasOccipital BoneMuscle, Smooth, VascularMuscle ContractionMuscle, SkeletalMuscle ProteinsNeuromuscular AgentsSpinal Cord InjuriesMuscle Fibers, SkeletalElectromyographyHemifacial SpasmBotulinum Toxins, Type ARelaxation TherapyMotor NeuronsMuscle DevelopmentMuscle FatigueMuscle Fibers, Fast-TwitchCoronary VasospasmMuscle DenervationMuscle Fibers, Slow-TwitchMyocytes, Smooth MuscleFacial MusclesMitochondria, MuscleNitric OxideVasodilationEsophageal Spasm, DiffuseTracheaOculomotor MusclesAcetylcholineIsometric ContractionMuscle, StriatedPapillary MusclesMuscle SpindlesElectric StimulationRespiratory MusclesCyclic GMPMuscle WeaknessRabbitsDeuteroporphyrinsCalciumVasodilator AgentsAbdominal MusclesMuscle CellsQuadriceps MuscleHSP20 Heat-Shock ProteinsNeuromuscular BlockadeNitroprussideMasticatory MusclesGuinea PigsMasseter MuscleNeuromuscular Nondepolarizing AgentsDose-Response Relationship, DrugTime FactorsPenisIntercostal MusclesRelaxationEndothelium, VascularErgonovineRats, Sprague-DawleyMuscle TonusMuscle Relaxants, CentralMuscular AtrophySatellite Cells, Skeletal MuscleNeuromuscular JunctionAorta, ThoracicRats, WistarAortaAngina Pectoris, VariantOpossumsBiomechanical PhenomenaPectoralis MusclesIsoproterenolNitroarginineCyclic GMP-Dependent Protein KinasesNitric Oxide DonorsNitroglycerinMuscular DiseasesOxadiazolesBiological FactorsMyofibrilsAnal CanalGuanylate CyclasePsoas MusclesNitric Oxide SynthaseDogsTemporal MuscleVasoconstrictionVasoactive Intestinal PeptideEnzyme InhibitorsAndrostanolsPenile ErectionMembrane PotentialsHindlimb