title: Ligustrazine and the contractile properties of soleus muscle in hindlimb-unloaded rats.
abstract: BACKGROUND
  In this study we investigated the effects of different dosages of ligustrazine (tetramethylpyrazine, Tmp) on soleus function and sarco(endo)plasmatic reticulum Ca(2+)-ATPase (SERCA) activity in 14-d hindlimb-unloaded (HU) rats.
  
  
  METHODS
  Female Sprague-Dawley rats were randomly divided into 4 groups (8 rats in each group): synchronous control (CON); HU plus intragastric water instillation (HU-W); HU plus different dosages of instilled Tmp (high: 42.53 mg x kg(-1), HU-TmpH; low: 21.15 mg x kg(-1), HU-TmpL). Muscle contraction force was examined in the soleus muscle. SERCA activity was assayed according to the released inorganic phosphate content.
  
  
  RESULTS
  As expected, in HU-W, soleus peak twitch tension (Pt), peak tetanic tension (P0), time to 50% peak tension (TP50), time to peak tension (TPT), time from peak tension to 50% relaxation (RT50), and SERCA activity decreased, all compared with CON. HU-TmpH Pt and P0 values were 179% and 90% above HU-W, and 187% and 124% above HU-W in HU-TmpL, respectively. TP50 and TPT values were 148% and 80% slower than HU-W with HU-TmpH and 95% and 32% in the HU-TmpL group, respectively. RT50 was slower than HU-W by 21% in HU-TmpH; SERCA activity elevated by 56% with HU-TmpH and by 72% with HU-TmpL.
  
  
  CONCLUSIONS
  Ligustrazine may alleviate the decrease of muscle contractile force and increase of shortening velocity in atrophied soleus, possibly by means of elevated sarcoplasmic reticulum Ca(2+)-ATPase activity.
authors.affiliation: Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, Xi'an, China.
authors.forename: Siyuan
authors.initials: S
authors.lastname: Li
authors.forename: Zhe
authors.initials: Z
authors.lastname: Yang
authors.forename: Yunfang
authors.initials: Y
authors.lastname: Gao
authors.forename: Guangyue
authors.initials: G
authors.lastname: Li
authors.forename: Huiping
authors.initials: H
authors.lastname: Wang
authors.forename: Helmut G
authors.initials: HG
authors.lastname: Hinghofer-Szalkay
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004326:Drinking; D004435:Eating; D005260:Female; D019417:Hindlimb Suspension / Q000502:physiology*; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D009206:Myocardium / Q000201:enzymology; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage*; D011719:Pyrazines / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism
chemical_list: D010975:Platelet Aggregation Inhibitors; D011719:Pyrazines; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; C017953:tetramethylpyrazine