weighedlick

Lickvolumedeterminedbyfoodschedulesinrab*ARTHURs.
WILSONandJOSEPHJ.
BARBORIAKVeteransAdministrationCenter,WoodandDepartmentsofPsychiatryandPharmacologyMarquetteSchoolofMedicine,Milwaukee,Wis.
53193Thenumberoflicksandfluidconsumedwererecordedseparatelyfor10ratsduringa7.
dayadjustmentperiodfollowedbya33-dayperiodduringwhichtheanimalswerefedforonly2heachday.
Significantdifferencesinthenumberoflickspermilliliterofwaterconsumedbetweenfoodandno·foodperiodsappearedafterthefirstexperimentalweek.
Therewasasignificantdecreaseinlickratefromthefirsttothesecondhourofeachfeedingperiodandalsofromthefeedingtothenonfeedingperiod.
Useofalickcounttodeterminevolumesoffluidsingestedondifferentfeedingschedulescouldbemisleading.
Drinkometers,devicesthatdetectmouthcontactswithdrinkingspouts,havebeenusedtomeasurefluidconsumption.
Examplesoftheiruseincludedeterminationofdrinkingratefollowingwaterdeprivation(Stellar&Hill,1952),food·associateddrinking(Kissileff,1969),andtemporalcharacteristicsofdrinking(Allison&Castellon,1970).
Someofthestudieshaveindicatedthatlickvolume,i.
e.
,theamountofliquidintakeforeachlick,wasaconstant.
Subsequently,thisconstanthasbeenutilizedtodeterminevolumeoffluidconsumedwhenonlylickcountswererecorded(Kissileff,1969).
Possiblefactorsthatmaymodifytheamountoffluidperlick,suchaspresenceorabsenceofsolidfood,havenotbeenconsidered.
Thepurposeofthisstudywastoinvestigatethepossibleinterrelationshipbetweenlickvolumeandthepresenceorabsenceofsolidfood.
METHODTenmaleSprague·Dawleyratsweighingapproximately225gatthestartoftheexperimentservedasSs.
Eachanimalwasindividuallyhousedinanoperanta:LIJ400~~u.
3000.
.
.
.
I~0.
.
.
.
.
.
.
.
.
.
.
conditioningcage(ScientificPrototype)modifiedbyhavingafoodcupinstalledinonecorner.
Adrinkometer(BRS)wasattachedtoacalibrateddrinkingtubethathadastandard1/8-in.
metalspout.
Thisarrangementenabledrecordingoflicksoncumulativerecordersandcounters.
Thevolumeofwaterconsumedwasseparatelydetermined.
Eachanimalwasplacedinthecageandgivena7-dayadjustmentperiodofadlibfoodandwater.
Thefoodconsistedofgroundstandardratdiet(PurinaRatChow).
Waterandfoodintakewasmeasureddaily.
Theexperimentproperconsistedofa33-dayperiod,duringwhichtheanimalswerefedforonly2heachday(9:00-11:00a.
m.
).
Totalfluidconsumedandamountoffoodconsumedwererecordedattheendofeach2-hfeedingperiod,whilethenumberoflickswasrecordedhourlyduringthis2-hperiod.
Totallicksandfluidconsumedfortheremaining22hwerealsorecorded,andanimalswereweighedweekly.
RESULTSCurvesrepresentingtheaveragenumberoflickspermilliliterofwaterwerederivedLICKSIML,FOODAVAILABLE(2HR)t>--t()_LICKS/ML,FOODABSENT(22HR)"'-200C/l~0-----.
-0-------0U.
.
.
JZ100oCtLIJ:!
:0I1I23WEEK45Fig.
1.
Meannumberoflickspermlofwaterconsumedduringthefoodandno·foodperiodsforthe5experimentalweeks.
Psychon.
SeL,1970,Vol.
20(5)fromthelickandfluidconsumptionmeasuresoffoodandno·foodperiodsandappearinFig.
l.
Eachpointrepresentstheweeklyaverageforthefiveexperimentalintervals.
StatisticalanalysisofthesedatabyttestindicatesthatnodifferenceispresentduringthefirstweekJyperiod,buteachsubsequentpairofpointsissignificantlydifferent(plickduringthe2-hfeedingperiodwas.
0036ml,whichisnotsignificantlydifferentfromthatunderadlibconditions.
However,thelickvolumeduringtheremaining22h(.
0052ml)issignificantlyhigher(plickrateforeachofthe2hduringthefeedingperiodandanaveragerateperhourfortheremaining22hwhenfoodwasabsent.
Thegreatestfrequencyoflicksisfoundduringthefirsthouroffeeding.
Thereisasignificantreduction(plickrateandalsofromthefeedingtothenonfeedingperiod.
DISCUSSIONTheamountofwaterdeliveredforeachtonguelapduringthepreexperirnentalperiod(0.
0034m!
)issimilartothatpreviouslyobtainedbyothers(Stellar&Hill,1952)whenfoodisavailableadlib.
However,thenumberoflickspermilliliterissignificantlylowerduringperiodswhennofoodisavailablethanwhenfoodis25~20~'-oSxr.
fl15~~-Ju.
.
o10a::UJCO:::!
;::JZZ-2ndhour22hourperiod(over.
Ihr.
)II,I2345WEEKFig.
2.
Meannumberoflicksperhourduringthefoodandno-foodperiods.
'Theexcellenttechnicalassistanceof~1r.
PhilipDuncanisgratefullyacknowledged.
271present.
Thisdifferencebecameapparentonlyafterthefirstweekoffoodscheduling.
Thesignificantdifferenceinthenumberoflicksneededtoconsumeonemilliliterofwaterwhenfoodispresentcomparedtothenumberoflickswhenfoodisabsentclearlyindicatesthatlickvolumeisnotaconstant.
Thedifferenceinlickvolumegeneratedbythepresenceorabsenceoffoodcanprobablyberelatedtodifferencesinthefrequencyoflicksunderthesetwoconditions.
Inthepresenceoffood,theratapparentlylicksataratethatpreventsthefullamountofwaterfromreachingthetongue.
Thus,useofalickcounttodeterminevolumesofingestedfluidsbyratsondifferentfeedingschedulescouldbemisleading.
Also,examinationofthevolume-per-lickdataderivedfromthisexperimentindicatesthatananimal'sliquidintakecanbemodifiedbythepresenceofsolidfood.
REFERENCESALLISON,J.
,&CASTELLAN,N.
J.
Temporalchaxacteristicsofnutritivedrinkinginratsandhumans.
JournalofComparative&PhysiologicalPsychology,1970,70,116-125.
KISSILEFF,H.
R.
Food-associateddrinkingintherat.
JournalofCompaxativc&PhysiologicalPsychology,1969,67,284-300.
STELLAR,E.
,&HILL,J.
H.
Therat'srateofdrinkingasafunctionofwaterdeprivation.
JournalofCompaxative&PhysiologicalPsychology,1952,45,96-102.
AnoteontheeffectsofchlorpromazineuponulcerationintheratK.
SHEMBERG,P.
C.
GREEN,andJ.
GLINERBowlingGreenStateUniversity,BowlingGreen,Ohio43402Fourgroupsofratswereexposedtoahighlyulcerogenicprocedure.
Threeexperimentalgroupsweregivenprogrammedinjectionsofthreedifferentconcentrationsofchlorpromazineandacontrolgroupreceivedphysiologicalsaline.
Alldrugconcentrationssignificantlyreducedulcerationrelativetocontrols.
Thelowestconcentrationprovedleasteffectiveinthisregard,butnosimplelinearrelationshipwasfoundbetweendrugconcentrationandfrequencyofulceration.
Atentativehypothesisregardinganall-or-noneprotectivefunctionofthedrugwassuggested,andparametersforfutureresearchoutlined.
Therehasbeenasubstantialamountofresearchaimedatdiscoveringandelaboratingtheparametersrelevanttotheproductionofstress-inducedgastriculcersintherat(e.
g.
,conflict,Sawrey&Weisz,1956;conditionedfear,Mikhail,1969;andoperantcontroloveraversiveevents,Weiss,1968).
However,therehasbeenlittlesystematicresearchconcerningtheeffectsofdrugsonulcerdevelopment,and,moreparticularly,therehasbeenalmostnoworkontheeffectsofchlorpromazineasanantiulcerogenicagent.
Therearesuggestionsintheliteraturethatthisdrug,272alongwithothercentralneurotropicsubstances,mayeffectivelyreducestress-inducedgastriculcerationandthatitmaybemoreeffectiveinthisregardthansomeotheragents,i.
e.
,morphine,atropine,andothers(e.
g.
,Zabrodin,1965).
Thepresentresearchrepresentedaninitialefforttoexaminesomeoftherelationshipsbetweenchlorpromazineandgastriculcerationintheratinsomewhatgreaterdetailthanhasbeenreportedpreviously.
Onespecificpurposeofthisworkwastostudytheeffectsofchlorpromazineinahighlyulcerogenicstresssituationandtotestvaryingconcentrationsofthisdruginordertodetectpossibleprotectiveeffectswithinthisparadigm.
Thesecondspecificgoalwastoattempttodiscoveraconcentrationlevelofthedrugthateffectivelyreducesortotallyinhibitsulcerationinahighlystressfulsetting.
Thus,drugconcentrationscoveringawiderangewereselectedandthreevalueswithinthisrangewerestudied.
Itwaspredictedthatthesevalueswoulddemonstrateagenerallynegativelyrelatedlinearfunctionbetweenconcentrationlevelandthedegreeofgastricpathology.
DRUGThedrugutilizedwaschlorpromazine,25mg/cc(Smith,Kline,&French).
SUBJECTSSswere109maleLong-Evanshoodedrats,100-115daysoldandweighingbetween345and370gattimeoftesting.
Sswereassignedrandomlytooneoffourconditionsinwhichthestockdrugsolutionwasdilutedasindicated:1/50th(N=21);1/201h(N=20);1/lOth(N=27);andsalinecontrol(N=41).
APPARATUSTwelve11.
5x11.
5x12in.
Plexiglasboxesservedastestcages.
ThegridfloorsofthesecageswerewiredsothatscrambledelectricshockcouldbedeliveredSimultaneouslytoallboxesviafourGrason-StadlerEI064GSshockgenerators.
Allsidesofthetestcageswerecoveredbyblackcontactpapertoprovidevisualisolation.
ShockscheduleswereprogrammedviaanLVEtapeprogrammer,andstress-restcycleswerecontrolledbyanLYEMultifunctionIntervalTimer.
PROCEDUREThestress-restscheduleinvolvedfirstfood-deprivingallanimalsfor48h,placingthemintothetestcages,andexposingthemtoa36-hstress-restprocedure.
Thisconsistedofalternating2hofshock(stress)with2hofnoshock(rest).
Thus,allSsreceivedatotalof18hofstressand18hofrestona2-halternatingschedule.
Duringeach2-hshockperiodSsreceived120randompresentationsofa2.
0-mA,2-secfootshock.
Thisbasicschedulewasdevelopedviapreliminaryresearchandwasshowntobehighlyulcerogenic(i.
e.
,89%ofallpilotSsulceratedwhilenocontrolSsdeprivedforthetotal84-hperiodshowedgastricpathology).
ThefirstinjectionforTableINumberandPercentageofSsUlceratingPerGroupNumberPercentGroupNUlceratingUlcerating1/50th2112571/20th203151/10th27622Saline413586Psychon.
Sci.
,1970,Vol.
20(5)