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 BlockadeNitroprussideGuinea PigsMasticatory MusclesMasseter MuscleNeuromuscular Nondepolarizing AgentsTime FactorsDose-Response Relationship, DrugPenisEndothelium, VascularIntercostal MusclesRelaxationErgonovineRats, Sprague-DawleyMuscle TonusMuscle Relaxants, CentralMuscular AtrophySatellite Cells, Skeletal MuscleNeuromuscular JunctionAorta, ThoracicRats, WistarAortaBiomechanical PhenomenaAngina Pectoris, VariantOpossumsPectoralis MusclesIsoproterenolNitroarginineCyclic GMP-Dependent Protein KinasesNitric Oxide DonorsMuscular DiseasesNitroglycerinOxadiazolesBiological FactorsMyofibrilsAnal CanalGuanylate CyclaseNitric Oxide SynthasePsoas MusclesDogsTemporal MuscleVasoconstrictionEnzyme InhibitorsVasoactive Intestinal PeptideAndrostanolsCells, CulturedPenile ErectionMembrane Potentials