The effect of time at which plasma separation occurs on biochemical values in small island flying foxes (Pteropus hypomelanus)

Heparinized blood samples from 15 adult small island flying foxes (Pteropus hypomelanus) were stored at 22 degrees C for 0-, 6-, and 24-hr intervals prior to centrifugation and separation of plasma from erythrocytes. Mean plasma biochemical values of 16 analytes were determined from all samples. Mean values of blood urea nitrogen, creatinine, total protein, albumin, globulin, alkaline phosphatase, alanine transaminase, aspartate transaminase, cholesterol, calcium, sodium, and bilirubin did not change significantly over 24 hr at 22 degrees C. Glucose was decreased at 6 and 24 hr. Potassium and phosphorus increased and chloride decreased, respectively, between 6 and 24 hr.

Reptile anesthesia

Successful reptile anesthesia requires patience, planning, and understanding of normal anatomy and physiology in health and disease. Reptiles make good anesthetic patients because of their physiologic resilience. New drugs that are not only safe and efficacious, but also result in relatively short recovery times, have greatly enhanced the design of anesthetic regimens. Further studies are required to quantitatively evaluate the physiologic effects of drugs used and validate available monitoring modalities for use in a wide variety of reptiles.

Human ERRgamma, a third member of the estrogen receptor-related receptor (ERR) subfamily of orphan nuclear receptors: tissue-specific isoforms are expressed during development and in the adult

The nuclear receptor protein superfamily is a large group of transcription factors involved in many aspects of animal development, tissue differentiation, and homeostasis in the higher eukaryotes. A subfamily of receptors, ERRalpha and beta (estrogen receptor-related receptor alpha and beta), closely related to the ER, were among the first orphan nuclear receptors identified. These receptors can bind DNA as monomers and are thought to activate transcription constitutively, unaffected by beta-estradiol. Studies of the expression patterns of ERRalpha and gene disruption experiments of ERRbeta indicate that they play an important role in the development and differentiation of specific tissues in the mouse. In this work we demonstrate the existence in humans of a third member of this subfamily of receptors, termed ERRgamma, which is highly expressed in a number of diverse fetal and adult tissues including brain, kidney, pancreas, and placenta. The ERRgamma mRNA is highly alternatively spliced at the 5'-end, giving rise to a number of tissue-specific RNA species, some of which code for protein isoforms differing in the N-terminal region. Like ERRalpha and beta, ERRgamma binds as a monomer to an ERRE. A GAL4-ERRgamma fusion protein activates transcription in a ligand-independent manner in transfected HEK293 cells to a greater degree than either the GAL4-ERRalpha or -beta fusion proteins.

Cranial edema associated with a protein-losing nephropathy in a golden-mantled flying fox (Pteropus pumilus)

An adult golden-mantled flying fox (Pteropus pumilus) was diagnosed with nephrotic syndrome on the basis of the findings of proteinuria, hypoalbuminemia, hypercholesterolemia, and cranial edema. Membranoproliferative glomerulitis and interstitial nephritis were confirmed antemortem by renal biopsy. The bat had received seven injections of oxytocin in the period immediately prior to presentation. The possible role of oxytocin in the development of the nephropathy is discussed. Supportive care and treatment with a single plasma transfusion, furosemide, and prednisone led to a gradual but complete resolution of the nephrotic syndrome in this animal.

Two-dimensional echocardiographic anatomy of the snake heart (Python molurus bivittatus)

Two-dimensional echocardiography was performed on Burmese pythons (Python molurus bivittatus) to determine an optimal echocardiographic imaging technique for snakes and to describe the echocardiographic anatomy of the snake heart. Five snakes immobilized with tiletamine/zolazepam and maintained on isoflurane in oxygen were imaged in dorsal recumbency. The portion of the snake's body containing the heart was submerged in warm water to reduce the artifact created by air trapped between and under the scales. Imaging in sagittal planes demonstrated the caudal vena cava, sinus venous valve, right atrium, various portions of the ventricle, horizontal septum, the left aortic arch, and pulmonary artery. Transverse imaging depicted the spatial relationship of the left and right aortic arches and pulmonary artery and the horizontal septum. Basic knowledge of cardiac blood flow in the reptile was necessary to understand the echocardiographic anatomy.

Critical care monitoring

Critical care monitoring in exotic practice is limited by the small size and the physiologic diversity of many patients. However, many of the principles applied to humans and other mammals can be extrapolated to monitoring in exotic animals. Advances in the monitoring of human patients offer the potential for more practical, low-cost monitoring in critical exotic patients in the future.

The putative cofactor TIF1alpha is a protein kinase that is hyperphosphorylated upon interaction with liganded nuclear receptors

Ligand-induced gene activation by nuclear receptors (NRs) is a complex process requiring dissociation of corepressors and recruitment of coactivators. The putative transcriptional intermediary factor TIF1alpha has been previously characterized as a nuclear protein that interacts directly with the AF-2 ligand-dependent activating domain present in the ligand-binding domain of numerous steroid and nonsteroid receptors, including the estrogen (ERalpha) and retinoid X (RXRalpha) receptors. We report here that TIF1alpha is both a phosphoprotein and a protein kinase. TIF1alpha coexpressed in COS-1 cells with RXRalpha or ERalpha is phosphorylated and becomes hyperphosphorylated upon ligand treatment. This hyperphosphorylation requires the binding of TIF1alpha to transcriptionally active NRs since it is prevented by mutations either in the core (alpha-helix 12 of the ligand-binding domain) of the AF-2 activating domains of RXRalpha and ERalpha or in the NR box of TIF1alpha that are known to prevent TIF1alpha-NR interactions. Thus, TIF1alpha is a phosphoprotein that undergoes ligand-dependent hyperphosphorylation as a consequence of nuclear receptor binding. We further show that purified recombinant TIF1alpha possesses intrinsic kinase activity and that, in addition to autophosphorylation, TIF1alpha selectively phosphorylates the transcription factors TFIIEalpha, TAFII28, and TAFII55 in vitro. These latter results raise the possibility that TIF1alpha may act, at least in part, by phosphorylating and modifying the activity of components of the transcriptional machinery.

Heartworm (Dirofilaria immitis) disease and glomerulonephritis in a black-footed cat (Felis nigripes)

A 6-yr-old, 1.36-kg, intact female black-footed cat (Felis nigripes) was presented to the Veterinary Medical Teaching Hospital, University of Florida, with a history of depression, lethargy, and anorexia. Cardiac dysfunction and renal failure were diagnosed on the basis of antemortem and postmortem findings. At necropsy, heartworms (Dirofilaria immitis), glomerulonephritis, and endometritis were present. The glomerulonephritis could have been immune mediated and may have been associated with the heartworm infection or the chronic endometritis or both. Heartworm disease should be included in the list of differential diagnoses for any exotic cat housed outdoors in an endemic heartworm region that dies peracutely or has suggestive gastrointestinal or respiratory signs. Heartworm prophylaxis and annual serologic testing in exotic cats housed outdoors in heartworm endemic regions are recommended.

The effects of short-term physical restraint and isoflurane anesthesia on hematology and plasma biochemistry in the island flying fox (Pteropus hypomelanus)

The effects of short-term physical restraint and isoflurane anesthesia on hematologic and serum biochemistry parameters were evaluated in 12 island flying foxes (Pteropus hypomelanus). Physical restraint was associated with significantly decreased calcium, cholesterol, globulin, albumin, hemoglobin concentrations, red blood cell count, and hematocrit and increased glucose, phosphorus, and potassium concentrations. Isoflurane restraint was associated with significantly decreased calcium, cholesterol, albumin, globulin, and glucose concentrations, aspartate transaminase and alkaline phosphatase activities, white blood cell count, red blood cell count, hemoglobin, hematocrit, and total neutrophil and lymphocyte counts and significantly increased phosphorus and chloride concentrations. For those variables where both restraint forms produced an alteration (red blood cell count, hemoglobin, hematocrit, calcium, phosphorus, glucose), the magnitude of change was always significantly greater for the physically restrained animals. This study indicates that in adult flying foxes isoflurane anesthesia is preferable to physical restraint for collection of blood samples for hematologic and plasma biochemical analysis. Additionally, blood samples should be collected as soon as possible after capture, regardless of restraint technique.

Comparative rectal bacterial flora of four species of flying fox (Pteropus sp.)

The rectal anaerobic and aerobic bacterial flora of four species of flying foxes were determined and compared. Four bacterial species were found in > or = 1 individual from each bat species at a significant (> or = 10%) level of the bacterial population: alpha-hemolytic Streptococcus sp. (41 of 56 bats), Enterococcus sp. (25/56), Escherichia coli (21/ 56), and group D Streptococcus sp., not Enterococcus sp. (9/56). Five other microbial species were also found in all four flying fox species, but at less significant percentages (found in at least one bat species, > or = 5% and < or = 10% of the recovered microbial population). These were nonhemolytic Streptococcus sp. (30/56), yeast (26/56), Corynebacterium sp. (25/56), Staphylococcus sp. (25/56), and Staphylococcus aureus (22/56). The majority of the species found were gram-positive, and only two obligate anaerobes, a Lactobacillus and a Bacteroides sp., were recovered from one bat.

Hematologic and plasma biochemical reference values for three flying fox species (Pteropus sp.)

Reference hematologic and plasma biochemical values from island (Pteropus hypomelanus), Malaysian (P. vampyrus), and Rodriquez Island (P. rodricensis) flying foxes were determined. In comparison to other mammals, these bats had very low plasma cholesterol and urea levels, which may be related to diet. The predominant white blood cells observed in P. hypomelanus and P. vampyrus were lymphocytes, while in P. rodricensis they were neutrophils. Elevated plasma levels of calcium, phosphorus, and alkaline phosphatase observed in the juvenile P. hypomelanus were expected, given the greater osteogenic activity of growing animals. In P. hypomelanus, bilirubin levels were higher in juveniles than in adults, and cholesterol levels were higher in females than in males.

Mycobacterium avium-intracellulare infection in a white-faced saki (Pithecia pithecia)

Physical examination of an adult female white-faced saki (Pithecia pithecia) revealed midabdominal multiple cystic structures. The animal developed a grade 3/4 reaction to old mammalian tuberculin injected into the right eyelid. Significant clinicopathologic findings included marked hyperproteinemia (9.2 g/dl), hyperglobulinemia (6.1 g/dl), and hypoalbuminemia (3.1 g/dl). Ultrasonography revealed multiple abdominal masses of varying echogenicity. The animal was euthanized and necropsied. Significant histopathologic findings included multifocal lymphadenitis with cystic degeneration of multiple visceral lymph nodes. Mycobacterium avium-intracellulare was cultured from a mesenteric lymph node.

Cardiopulmonary effects of carfentanil in dama gazelles (Gazella dama)

Sixteen (10 female, six male) captive-born dama gazelles (Gazella dama) weighing 48 +/- 10 kg (mean +/- SD) were used to evaluate the cardiopulmonary effects of i.m. carfentanil and to validate the use of pulse oximetry in immobilized gazelles. Carfentanil (18.4 +/- 2.2 micrograms/kg i.m.) produced rapid induction (6 +/- 3 min), moderate muscle relaxation, and a significant (P < 0.05) decrease in heart rate (87 +/- 12 beats/min) beginning 5 min following induction and continuing throughout the immobilization period. A decrease in respiratory rates began 15 min following induction (11 +/- 4 breaths/min). Systemic hypertension was present throughout the immobilization period. Arterial blood gas analysis, performed at 10, 20, and 30 min after induction, showed PaCO2 and PaO2 values within normal limits. Arterial blood oxygen saturation (SaO2) was < 95% 10 min after induction. Relative arterial oxygen saturation (SpO2) values indicated by pulse oximetry were generally lower than SaO2 values but reliably demonstrated trends in arterial oxygen saturation as confirmed by arterial blood gas analysis. Periods of hypoxemia were usually indicated by the pulse oximeter reading and confirmed by SaO2 measurements. There was an increase in creatine phosphokinase values (88 +/- 53 U/L to 109 +/- 48 U/L) at 30 min postimmobilization. Naltrexone reversal (1.8 +/- 0.3 mg/kg, half i.v. and half s.c.) was rapid and uneventful, and time to standing was 2 +/- 1 min.

Avian pox in eastern screech owls and barred owls from Florida

Avian pox was diagnosed in two eastern screech owls (Otus asio) and two barred owls (Strix, varia) living in different regions of Florida (USA) between November 1994 and October 1995. Avian poxvirus infection was confirmed by the presence of eosinophilic intracytoplasmic epidermal inclusions (Bollinger bodies) on light microscopy of tissue from all four owls. Additionally, typical poxvirus particles were demonstrated by electron microscopy of a lesion from one of the eastern screech owls. These are the first published case reports of avian pox in eastern screech owls and barred owls.

SUG1, a putative transcriptional mediator and subunit of the PA700 proteasome regulatory complex, is a DNA helicase

Yeast SUG1 was originally characterized as a transcriptional mediator for the GAL4 transactivator. A similar role in vertebrates was suggested by the ligand-enhanced interaction between mammalian homologues of yeast SUG1 and the ligand-dependent activating domain (AF-2) of nuclear receptors. SUG1 was also shown to be a component of the PA700 regulatory complex of the 26 S proteasome and a member of a large family of putative ATPases. However, no catalytic function has yet been attributed to SUG1. We show here that SUG1 is a 3'-5' DNA helicase whose activity is dependent on an intact ATP binding domain. The sedimentation heterogeneity of mammalian SUG1 suggests that it may be associated with distinct protein complexes and therefore play multiple roles.

hTAF(II)68, a novel RNA/ssDNA-binding protein with homology to the pro-oncoproteins TLS/FUS and EWS is associated with both TFIID and RNA polymerase II

TFIID is the main sequence-specific DNA-binding component of the RNA polymerase II (Pol II) transcriptional machinery. It is a multiprotein complex composed of the TATA-binding protein (TBP) and TBP-associated factors (TAF(II)s). Here we report the cloning and characterization of a novel human TBP-associated factor, hTAF(II)68. It contains a consensus RNA-binding domain (RNP-CS) and binds not only RNA, but also single stranded (ss) DNA. hTAF(II)68 shares extensive sequence similarity with TLS/FUS and EWS, two human nuclear RNA-binding pro-oncoproteins which are products of genes commonly translocated in human sarcomas. Like hTAF(II)68, TLS/FUS is also associated with a sub-population of TFIID complexes chromatographically separable from those containing hTAF(II)68. Therefore, these RNA and/or ssDNA-binding proteins may play specific roles during transcription initiation at distinct promoters. Moreover, we demonstrate that hTAF(II)68 co-purifies also with the human RNA polymerase II and can enter the preinitiation complex together with Pol II.

Comparative cardiopulmonary effects of intramuscularly administered etorphine and carfentanil in goats

OBJECTIVE

To determine comparative cardiopulmonary effects of IM administered etorphine and carfentanil in goats.

ANIMALS

Seven clinically normal adult female goats.

DESIGN

Each goat received at least 9 drug treatments (etorphine HCl, 5 [twice], 10, 20, and 40 and carfentanil citrate, 5, 10, 20 and 40 micrograms/kg of body weight), with a minimal 2-day interval between trials. Although drug dosages were randomized, etorphine and carfentanil treatments were alternated. To assess for drug tolerance, the first and last treatments always were etorphine (5 micrograms/kg).

PROCEDURE

All goats were instrumented for long-term cardiopulmonary variable data collection.

RESULTS

Both drugs induced rapid catatonic immobilization, characterized by limb and neck hyperextension, with occasional vocalization and bruxation. Etorphine elicited transient violent struggling and vocalization immediately. Time to immobilization appeared dose-dependent, and was more rapid with carfentanil (< or = 5 minutes) than etorphine (5 to 10 minutes) at all dosages. Recovery to standing occurred earlier for etorphine (1 to 2 hours) than carfentanil (> 2 hours) at all dosages. Both drugs at all dosages significantly (P < or = 0.05) increased systemic and left ventricular (LV) end-diastolic pressures, LV peak negative dP/dt, total peripheral resistance (TPR), hemoglobin concentration, and left atrial (LA) and pulmonary O2 contents. They also significantly decreased heart and respiration rates, and TPR. A significant increase was observed at some dosages for LV stroke volume and index, LV peak positive dP/dt, mean pulmonary artery pressure, PaO2, pulmonary artery oxygen partial pressure, PaCO2, pulmonary mixed venous carbon dioxide partial pressure, LA hemoglobin saturation, LA transport index, and body temperature. Pulmonary and systemic mixed venous carbon dioxide and oxygen contents were significantly decreased at some dosages.

CONCLUSIONS

Intramuscularly administered etorphine and carfentanil induce hypertension, bradycardia, and bradypnea in goats. The hypertension appears attributable to an increase in TPR.

CLINICAL RELEVANCE

Although the cardiopulmonary effects of carfentanil occurred more rapidly, these effects were similar in magnitude for etorphine and carfentanil over the evaluated dosage range.

An upstream U-snRNA gene-like promoter is required for transcription of the Arabidopsis thaliana 7SL RNA gene

The genes transcribed by RNA polymerase (pol) III can be placed into four distinct groups based on the nature and position of their promoter elements. In the higher eukaryotes equivalent genes usually belong to the same sub-type of pol III promoters and there are few examples of genes which have changed promoter type during evolution. In this work we demonstrate that the promoter of the Arabidopsis thaliana 7SL RNA gene is located upstream of the coding region and is identical to the promoters of pol III-specific plant U-small nuclear RNA (U-snRNA) genes. Sequence analysis of two different 7SL genes from A. thaliana revealed that both genes contain two sequence elements in their 5' flanking regions identical in sequence and position to the highly conserved USE and TATA elements of the pol III-transcribed plant U-snRNA genes. Mutational analysis of these elements in the At7SL-2 gene indicates that the USE and TATA elements are both necessary and account for > or = 90% of the transcriptional activity of this gene in transfected plant protoplasts. Within the coding region of both genes there is a sequence element which is a 10/11 nt match to the consensus B-box element of tRNA genes, however, this element is not important for gene activity. These findings distinguish the plant genes from the human 7SL gene, which has both internal and upstream promoter elements and its upstream elements are different from those found in the human U-snRNA genes.

Principles and techniques of anesthesia and analgesia for exotic practice

Principles and techniques of anesthesia and analgesia for small animal exotic practice are described. The use of regimens based around inhalation anesthesia are recommended over injectable anesthetics. Techniques of perianesthetic monitoring and support are described and emphasized. The article concludes with a discussion of anesthesia for specific exotic animals likely to be encountered in small animal practice.

Both Arabidopsis TATA binding protein (TBP) isoforms are functionally identical in RNA polymerase II and III transcription in plant cells: evidence for gene-specific changes in DNA binding specificity of TBP

Promoters of pol II and pol III transcribed U-snRNA genes in plants have identical sequence elements comprised of a -30 TATA box and an upstream sequence element (USE), located four or three helical turns upstream of the TATA box in pol II and pol III genes, respectively; it is this difference in element spacing that determines the RNA polymerase specificity of the gene. We are interested in identifying factors binding to U-snRNA gene promoters and their role in selection of RNA polymerase. In this work we have investigated possible differences in the activity of the two TATA binding proteins (TBPs) encoded by two different TBP genes of Arabidopsis. Using mutant TBPs with altered DNA binding specificity, similar to those described previously in yeast, we show that two Arabidopsis TBP isoforms are equally active with both pol II and pol III U-snRNA genes and with an mRNA gene transfected into plant protoplasts. In contrast to yeast, where modified TBP permits transcription only from promoters containing the TGTAAA mutant of the consensus (TATAAA) TATA element, altered Arabidopsis TBPs also suppress other TATA box mutants. Similar results were obtained with human and yeast TBP mutants expressed in plant cells. Interestingly, in several cases suppression of different TATA box mutants by altered TBPs was gene or RNA polymerase specific suggesting that assembly of TBP into specific complexes containing different TBP-associated factors may alter DNA binding specificity of the protein.

Thyroid and adrenal function tests in adult male ferrets

Effects of thyroid-stimulating hormone (TSH) and thyrotropin-releasing hormone (TRH) on plasma concentrations of thyroid hormones, and effects of ACTH and dexamethasone on plasma concentrations of cortisol, were studied in adult male ferrets. Thirteen ferrets were randomly assigned to test or control groups of eight and five animals, respectively. Combined (test + control groups) mean basal plasma thyroxine (T4) values were different between the TRH (1.81 +/- 0.41 micrograms/dl, mean +/- SD) and TSH (2.69 +/- 0.87 micrograms/dl) experiments, which were performed 2 months apart. Plasma T4 values significantly (P less than 0.05) increased as early as 2 hours (3.37 +/- 1.10 micrograms/dl) and remained high until 6 hours (3.45 +/- 0.86 micrograms/dl) after IV injection of 1 IU of TSH/ferret. In contrast, IV injection of 500 micrograms of TRH/ferret did not induce a significant increase until 6 hours (2.75 +/- 0.79) after injection, and induced side effects of hyperventilation, salivation, vomiting, and sedation. There was no significant increase in triiodothyronine (T3) values following TSH or TRH administration. Combined mean basal plasma cortisol values were not significantly different between ACTH stimulation (1.29 +/- 0.84 micrograms/dl) and dexamethasone suppression test (0.74 +/- 0.56 micrograms/dl) experiments. Intravenous injection of 0.5 IU of ACTH/ferret induced a significant increase in plasma cortisol concentrations by 30 minutes (5.26 +/- 1.21 micrograms/dl), which persisted until 60 minutes (5.17 +/- 1.99 micrograms/dl) after injection. Plasma cortisol values significantly decreased as early as 1 hour (0.41 +/- 0.13 micrograms/dl), and had further decreased by 5 hours (0.26 +/- 0.15 micrograms/dl) following IV injection of 0.2 mg of dexamethasone/ferret.(ABSTRACT TRUNCATED AT 250 WORDS)

Use of halothane to maintain anesthesia induced with etorphine in juvenile African elephants

Sixteen 3- to 5-year-old African elephants were anesthetized one or more times for a total of 27 diagnostic and surgical procedures. Xylazine (0.1 +/- 0.04 mg/kg of body weight, mean +/- SD) and ketamine (0.6 +/- 0.13 mg/kg) administered IM induced good chemical restraint in standing juvenile elephants during a 45-minute transport period before administration of general anesthesia. After IM or IV administration of etorphine (1.9 +/- 0.56 micrograms/kg), the mean time to lateral recumbency was 20 +/- 6.6 and 3 +/- 0.0 minutes, respectively. The mean heart rate, systolic blood pressure, and respiration rate during all procedures was 50 +/- 12 beats/min, 106 +/- 19 mm of Hg, and 10 +/- 3 breaths/min, respectively. Cardiac arrhythmias were detected during 2 procedures. One elephant with hypotension responded to a decrease in the concentration of halothane and IV infusion of dobutamine HCl. Alterations in systolic blood pressure, ear flapping, and trunk muscle tone were useful for monitoring depth of anesthesia. Results indicated that halothane in oxygen was effective for maintenance of surgical anesthesia in juvenile African elephants after induction with etorphine.

Bacteremia and septic arthritis in a West African dwarf crocodile

An anorectic, adult West African dwarf crocodile was examined because of bilateral hind limb paresis. Clinical findings included multiple skin wounds, osteomyelitis of the distal portions of the right radius and ulna, severe anemia, and Serratia marcescens bacteremia. The crocodile died after a blood transfusion. At necropsy, hemorrhage in the subarachnoid space, suppurative polyarthritis, and gastric ulceration were found. Serratia marcescens and Morganella morganii were isolated from multiple tissues and body fluids. It was concluded that the bilateral paresis was caused by severe septic arthritis secondary to bacteremia, and that the crocodile died from spinal injury caused by the blood transfusion into the supravertebral vein.

Effects of oxygen supplementation on blood gas values in chemically restrained juvenile African elephants

Arterial oxygen and carbon dioxide tensions were determined in sedated immature African elephants and in elephants immobilized with etorphine hydrochloride or with an etorphine-ketamine combination. For manipulative and surgical procedures, the Hudson demand valve was used for oxygen supplementation during 6 procedures, and insufflation was used during 2 procedures. The Hudson demand valve was more effective than insufflation in sustaining adequate arterial oxygenation.

Effect of acepromazine on the anesthetic requirement of halothane in the dog

Five adult dogs were used to determine whether acepromazine maleate (ACP), administered IM, decreases the maintenance requirement of halothane and to measure any decrease for the ACP dosages of 0.02, 0.04, 0.06, 0.08, 0.10, and 0.20 mg/kg. The value minimal alveolar concentration, a measure of anesthetic potency, was used as the measure of anesthetic requirement of halothane before and after ACP was administered. All dogs were randomly exposed to each dosage of ACP, as well as to control of 0.2 ml of sterile water. At all dosages of ACP, the decrease in the minimal alveolar concentration of halothane was significant (P less than or equal to 0.05) when compared with that of the control. The decreases at the 0.04 and 0.20 mg/kg dosages were significantly (P less than or equal to 0.05) greater than those at the 0.02 and 0.06 mg/kg dosages. Halothane requirements at all other ACP dosages (0.08 and 0.10 mg/kg) were not significantly different from each other or from those at any of the other dosages. The percentage of decrease in anesthetic requirement after ACP was administered varied from 34% to 46%, with a mean decrease of 40%. The largest decrease was recorded at the dosage of 0.04 mg/kg.