| pharmacology | screening | assay | |||
| NMB | A ) competitive w competes e ach at nicotinic receptors eg :1-d-tubocurarine 2-gallamine 3-vecuronium B) non competitive w initiates depolarisatn as ach but is maintained eg :1-succinyl choline 2-Decamethonium (it is not necessary for 2 blockers to give additive effect when used together | 1) general primary tests | 1-() griping strength 2-() limb tone 3-unable to remain on resolving drum or steep loop plate 4-loss of righting reflex (give an idea if it may be NMB because CNS depressant cause the same) | 1 )rabbit head drop method | *by inject std curare >gradually (ml/min) >till full curarinisation >full stretched toneless head >vol *then use test *determine conc of test by : cv=cv |
| 2 )chick method | inject subs in wing vein *if competitive >flaccid paralysis *if non >spastic (diff () 2 types) | 2) nerve -mucle prep (both can diff () both type) a)cat sciatic nerve & tipials interior muscle | *stim of sciatic N >contractn *NMB >inhibit cont (det 50% reductn in cont) *adv 1-cat similar to human in sensitivity to NMB 2-in situ prep (not need ph soln) *disadv :general anaethesia + relaxation with competitive NMB so we use chlorolase G A | ||
| 3)Rabbit head drop method | NMB injected in ear vein >head drop (toneless) as NMB cause paralysis in neck ,trunk ,limbs ,respiratory muscle | b) rat frenic nerve prepn | *separate diaphragm e frenic nerve and place in p.soln and do the expriment *measure amount of NMB that cause 50% reductn | ||
| 3) frog rectus abdominus | |||||
| histamine & anti histamine | a))) for histamine 1-G pig ileum or tacheal chain | very sensitive to hist *but we do atropinization first to block muscarinic receptor *then add std hist > contr >matching | b))) for anti histamine 1-G.pig ileum & trachea | amount that cause 50% decrease in contractn (matching) | |
| 2-cat blood pressure | *hist ! Bl p *to be sure give antihist >block fall in bl p | 2-modificatn of anaphylactic response | *we induce release of indogenous hist (by sensitization of G pig by egg albumin and after 3 weeks ,give another dose of alb >ag-ab reaction >hist >convulsions (det preconvulsive time) *and then repeat after giving antihist (preconvulsive) | ||
| 3-hist aerosol (2% hist) (screening) | *g.pig in closed transparent box >dysnea -asphyxia -convulsions -death *to be assayed =det time for death of std & test | 3-protectn against hist aresol (bioassay) | *preconvulsive time >till convulsion (t1) then the rest (for 2 days) *on the same g pig :antihist (20m) and then give hist >till convulsion (t2) >longer time *and then compare the prolongation of preconvulsive time for both std & test *** if the animal remains for 6 min with normal resp after hist aresol >called protection (for 50% of animals) '>conc compared e test | ||
| serotonin | 1-rat uterus in osterous stage | *in dejalon soln *std & test match | |||
| 2-rat stomach fundus strip | *very sp to %-HT *the fundal part is cut away to obtain continous strip *kreb's soln *5-Ht >contr *std & test match | ||||
| mixtures | ach & hist | *ach >Froh rectus A *then add atropine and assay hist on ileum | ach ,5-HT | ach on FRA *atropine then fundus | ***hist & E :: *assay E in presence of mepyramine 2-E is decomposed by render soln alkali at 10c 3-then do histamine assay |
| ach & NE | *ach on FRA *then add atropine ,assay NE (pithed rat or spinal cat) | *hist ,5-HT | *block hist receptor by mepyramine ,assay 5-HT using fundus *bolck 5-Ht receptor by LSD ,Buspar or cyproheptadine >assay hist on G pig ileum | ||