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Human and animal behaviour often combine into a perfect storm of obesity-causing actions., (British Veterinary Association.)

Background: The purpose of this study was to evaluate the values of Schirmer tear test (STT) and determine effects of age, life stage, sex, breed and neuter status on tear production in healthy cats., Methods: Three hundred and forty-three domestic shorthair (DSH) and Persian cats, 50 days through 18 years old, were examined in this study. STT I was used to measure tear production in both eyes of each cat., Results: A mean STT 14.9±4.8 mm/min was calculated for the eyes of all cats. There was a significant difference between STT values in kittens (≤6 months old) and cats of other age groups (P<0.001). A substantial number of cats with clinically normal eyes had STT values less than 10 mm/min. No significant difference was found between males (14.7±5.0 mm/min) and females (15.1±4.5 mm/min) in STT values (P=0.46). Significant differences were found between entire (14.4±4.2 mm/min) and neutered (16.2±4.1 mm/min) cats (P=0.001), and between STT values of DSH (14.6±5.0 mm/min) and Persian (16.5±3.1 mm/min) cats in the study population (P=0.001)., Conclusions: This study documents the average STT values for a sizeable feline population demonstrating that, in contradistinction to the situation in dogs, a number of cats with clinically normal eyes have STT values below 10 mm/min., Competing Interests: Competing interests: None declared., (© British Veterinary Association 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

The degenerative effects of ageing on the kidneys have been extensively studied in humans. However, only recently interest has been focused on renal ageing in veterinary medicine. Contrast-enhanced ultrasound allows non-invasive evaluation of renal perfusion in conscious cats. Renal perfusion parameters were obtained in 43 healthy cats aged 1-16 years old, and the cats were divided in four age categories: 1-3 years, 3-6 years, 6-10 years and over 10 years. Routine renal parameters as serum creatinine, serum urea, urine-specific gravity, urinary protein:creatinine ratio and systolic blood pressure were also measured. No significant differences in any of the perfusion parameters were observed among the different age categories. A trend towards a lower peak enhancement and wash-in area under the curve with increasing age, suggestive for a lower blood volume, was detected when comparing the cats over 10 years old with the cats of 1-3 years old. Additionally, no significant age-effect was observed for the serum and urine parameters, whereas a higher blood pressure was observed in healthy cats over 10 years old., Competing Interests: Competing interests: None declared., (© British Veterinary Association (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Rectal temperature measurement (RTM) can promote stress and defensive behaviour in hospitalised cats. The aim of this study was to assess if axillary temperature measurement (ATM) could be a reliable and less stressful alternative for these animals. In this prospective study, paired rectal and axillary temperatures were measured in 42 cats, either by a veterinarian or a student. To assess the impact of these procedures on the cat's stress state, their heart rate was checked and a cat stress score (CSS) was defined and graded from 1 (relaxed) to 5 (terrified). A moderate correlation was found between RTM and ATM (r=0.52; P<0.0001). RTM was on average 0.9 °C (1.6 °F) higher than ATM (P<0.0001), although a wide variation was found in the difference between these two measurements (-2.1 °C to 3.6 °C (-3.8 °F to 6.5 °F)). ATM failed to identify hypothermia in 25 per cent of the cases and hyperthermia in 19 per cent of the cases but may be considered less stressful than RTM. Indeed, RTM induced a mildly greater increase in heart rate (+6 bpm; P=0.01) and in CSS (+0.2; P=0.001) than ATM. The results were not affected by operator type. In conclusion, RTM should remain the standard method to obtain accurate temperatures in cats., (British Veterinary Association.)

This study was designed to explore the effect of active immunization against maltose binding protein-gonadotropin releasing hormone I hexamer (MBP-GnRH-I6) on the reproductive function in cats. Each immunized cat was administered twice intramuscularly in the neck at 16 and 20 weeks old. The concentrations of the testosterone and estradiol and the level of anti-GnRH-I antibody in the serum were measured by radioimmunoassay and ELISA, respectively. The results showed that the weight and size of testicles and ovaries, and the concentrations of serum testosterone and estradiol in the immunized animals were lower than those of the control cats (P < 0.05), but that the levels of anti-GnRH-I antibody were significant higher compared to control animals (P < 0.05). Testicular tissues from the immunized male cats showed that seminiferous tubules were depauperate with the lumen relatively empty and that the differentiation of spermatogonia was not obvious. Tissues from the immunized female cats showed that the ovaries had many primordial follicles and primary follicles, but no secondary follicle was observed. These results showed active immunization against MBP-GnRH-I6 could make the gonads atrophy and reduce the concentrations of gonadal hormones, which suggested that MBP-GnRH-I6 was a very effective immunogen in the cat., (© 2015 Japanese Society of Animal Science.)

Feasibility, surgical time and complications of different surgical techniques for prepubertal gonadectomy (PPG; 8-12 weeks of age) in cats were studied and compared to gonadectomy at traditional age (TAG; 6-8 months of age). Kittens were randomly assigned to PPG or TAG. Ovarian pedicle haemostasis for PPG was achieved by ligatures (n=47), vascular clips (n=50), bipolar electrocoagulation (n=50), or pedicle tie (n=50); for TAG (n=34) ligatures were used. In male cats, PPG consisted of closed castration by spermatic cord knot (n=92) or ligature (n=91) while TAG (n=34) was an open castration by spermatic cord knot. A linear (surgical time) and a logistic regression (complications) model were designed. Significance was set at 0.05. For female PPG, clips and coagulation were the fastest procedures; placement of ligatures was most time-consuming. In male PPG, knot placement was significantly faster than ligation. In both sexes, very few intraoperative or wound complications were observed, irrespective of the surgical technique used. Surgical times in females (ligatures) as well as in males (knot) were significantly shorter for PPG than for TAG. PPG was as safe as TAG, yet took less time to perform and did not result in a greater rate of postoperative complications., (British Veterinary Association.)

This study evaluated the effects of adding an acidifying agent based on phosphoric acid (A), a yeast extract from a specific strain (Saccharomyces cerevisiae) (Y) and the combination of these two additives in food for adult cats. A test was conducted with 24 animals (mean 3.5 years old), mixed breed, weighing 3.72 ± 0.74 kg, kept in individual metabolic cages and distributed in a completely randomized design with a 2 × 2 factorial design (with or without A 0.6% of dry matter, with or without Y 1.5% of dry matter) totalling four treatments and six replicates of each condition. The experimental period was 15 days. The A or the Y reduced (P< 0.01) the dry matter intake, but the effect was not observed when they were associated. The association improved (P<0.05) the digestibility of dry matter and ashes. The A reduced urine pH (P=0.05) regardless of the presence of the Y. There was no effect (P>0.09) on other parameters evaluated. Results of this study show that the isolated use of 0.6% A or 1.5% Y in diets for cats is not recommended. However, the association of these two additives was beneficial in increasing nutrient digestibility., (© 2014 Japanese Society of Animal Science.)

'Accidental' litters contribute to population growth and the number of unwanted animals entering animal welfare organisations. Assessing the problem's extent and determining risk factors enables identification of education targets. Data were obtained from 715 cat-owning households in a cross-sectional telephone survey. Demographic and lifestyle factors were assessed for their association with accidental litters and with owner knowledge of cat reproduction. A total of 128 litters were reported from 552 female cats, and the proportion of accidental litters reported by owners was 80 per cent. Multivariable analysis identified that respondents were more likely to report an accidental litter of kittens if they believed a female cat should have a litter prior to being neutered, if they had more than one cat and if they rented rather than owned their home. Misconceptions relating to cat reproduction were common. The opinion that the youngest age a cat could get pregnant was five months of age (or older) was held by 83.5 per cent of cat-owning respondents, with over a quarter (26.4 per cent; 174/659) believing a queen is unable to conceive until at least a year of age. Almost half the respondents (49.0 per cent; 334/682) believed a female cat should have a litter before being neutered or were not sure; 38.8 per cent (264/681) thought that un-neutered, related cats would not mate or were not sure. This study suggests that improving cat-owner knowledge of the reproductive capacity of cats is likely to have a significant impact on the numbers of accidental litters born.

Cats need a minimum amount of space even in animal shelters. In this study the effects of single caging and cage size on the behavior and stress level of domestic cats were investigated. Six neutered cats (2-15 years old) that had been housed in a group for at least 7 months were moved to three kinds of single cages (small, medium and large) by rotation on a Latin square design. They experienced each cage size for 6 days. Cats could use vertical dimensions when housed in a group room and the large cage. Behavioral observation was conducted for 3 h in the evening, and stress levels were assessed by urine cortisol-to-creatinine ratios. The amounts (estimated proportions) of time spent in locomotion and social/solitary play were lower even in large cages than in group housing (both P < 0.05). Conversely, the amount of time spent resting tended to increase when housed singly (P = 0.104). The urine cortisol-to-creatinine ratios of singly housed cats tended to be higher than that of group-housed cats (P = 0.086). The results indicate that cats become less active when they are housed singly in cages regardless of the cage size. Cats seem to feel no undue stress even in small cages if the stay is short., (© 2012 The Authors. Animal Science Journal © 2012 Japanese Society of Animal Science.)

Intra-abdominal pressure (IAP) and abdominal perfusion pressure (APP) have shown clinical relevance in monitoring critically ill human beings submitted to abdominal surgery. Only a few studies have been performed in veterinary medicine. The aim of this study was to assess how pregnancy and abdominal surgery may affect IAP and APP in healthy cats. For this purpose, pregnant (n=10) and non-pregnant (n=11) queens undergoing elective spaying, and tomcats (n=20, used as controls) presented for neutering by scrotal orchidectomy were included in the study. IAP, mean arterial blood pressure (MAP), APP, heart rate and rectal temperature (RT) were determined before, immediately after, and four hours after surgery. IAP increased significantly immediately after abdominal surgery in both female groups when compared with baseline (P<0.05) and male (P<0.05) values, and returned to initial perioperative readings four hours after surgery. Tomcats and pregnant females (P<0.05) showed an increase in MAP and APP immediately after surgery decreasing back to initial perioperative values four hours later. A significant decrease in RT was appreciated immediately after laparotomy in both pregnant and non-pregnant queens. IAP was affected by abdominal surgery in this study, due likely to factors, such as postoperative pain and hypothermia. Pregnancy did not seem to affect IAP in this population of cats, possibly due to subjects being in early stages of pregnancy.

The objective of this study was to evaluate the effects of in utero and postnatal exposure of a high-protein (HP; n=9) or moderate-protein (MP; n=16) diet on growth, and serum metabolite, ghrelin and leptin concentrations during the first 4 months of life in kittens. It was hypothesized that blood indices would be modified due to diet. Blood samples were collected from kittens at 4, 8, 12 and 16 weeks of age. Kittens were weaned at 8 weeks of age onto the same diet as the dam. Body weight was measured weekly from birth and daily food intake for each litter was recorded post-weaning. Serum concentrations of urea nitrogen, total protein and triglycerides were greater (P<0.05) in kittens fed the HP diet. Serum cholesterol concentrations were greater (P <0.05) in MP-fed kittens at 4 weeks of age. Moderate-protein fed kittens tended to have greater (P < 0.10) serum ghrelin concentrations. Leptin concentrations were not affected by diet, but changed over time (P<0.05). Our data indicate that diet and age of kittens affect circulating concentrations of peptides important in appetite regulation. Further research testing the effects of in utero and early postnatal nutrient exposure on feline obesity risk in adulthood is needed., (© 2011 The Authors. Animal Science Journal © 2011 Japanese Society of Animal Science.)

Thirty-nine healthy cats that were presented for ovariohysterectomy received intramuscular acepromazine (0.05 mg/kg) and subcutaneous meloxicam (0.3 mg/kg) as preanaesthetic medication. They were then randomly assigned to receive either propofol or alfaxalone by intravenous injection for induction of anaesthesia, administered to effect until tracheal intubation was possible. Anaesthesia was maintained with isoflurane in oxygen. Cardiorespiratory variables were measured before induction and every five minutes throughout anaesthesia. The recovery times and quality of recovery were also recorded. Data relating to one cat were omitted because it was found to be pregnant. The mean (sd) induction doses were 4.7 (1.2) mg/kg for alfaxalone and 7.5 (2.0) mg/kg for propofol. Postinduction apnoea was not observed. There were no significant differences in cardiorespiratory variables between the alfaxalone group (mean pulse rate [PR] 155 [18]) bpm, Doppler arterial blood pressure [DBP] 73 [6] mmHg, respiratory rate [RR] 31 [8] breaths/minute, end-tidal carbon dioxide partial pressure [PECO(2)] 3.7 [0.8] kPa) and the propofol group (PR 147 [16] bpm, DBP 77 [12] mmHg, RR 32 [8] breaths/minute, PECO(2) 3.7 [0.5] kPa). Recovery times were very similar and the quality of recovery was considered fair or good in most cats in both groups. The induction of anaesthesia, the cardiorespiratory variables and the recovery were clinically acceptable and similar after induction with either alfaxalone or propofol.

Eighty-four female cats undergoing ovariohysterectomy in a blinded, randomised, prospective clinical study were assigned to one of three groups of 28 to receive either 0.01 mg/kg buprenorphine (group B), 4 mg/kg carprofen (group C), or the same doses of both drugs (group BC). A dynamic and interactive visual analogue scale (DIVAS) from 0 to 100 mm, and a simple descriptive scale (SDS) from 0 to 4 were used to evaluate the cats' degree of analgesia and sedation for 24 hours postoperatively. There was no significant difference in the cats' sedation scores by SDS or DIVAS, and no difference in their pain scores by DIVAS. By SDS, the cats in group BC had significantly lower pain scores than the cats in group C (P<0.001) and group B (P<0.05). Nine of the cats in group B, nine in group C and five in group BC required rescue analgesia, and the cats in group C required rescue earlier than those in group B (P<0.05).

This study was designed to compare the effects of three doses of romifidine (200, 400 and 600 microg/kg) with medetomidine (80 microg/kg) administered intramuscularly to five cats. The quality of sedation and the cardiovascular and respiratory effects of each treatment were evaluated, and the onset and duration of the sedation, and the cats' recovery times, were measured. Cardiorespiratory variables were also analysed. The dose of 200 microg/kg romifidine was clinically superior to the other doses of romifidine, providing moderate sedation, with minor cardiorespiratory and other adverse effects. However none of the doses of romifidine induced as deep and reliable sedation as the dose of medetomidine.

In April 2004, a questionnaire was distributed to veterinary nurses across the UK to assess their attitudes towards the assessment and management of pain in practice. During the six-week collection period, a total of 541 questionnaires were returned, of which 24 (4.25 per cent) were discounted due to completion errors. Overall, the pain scores for procedures involving dogs were higher than those for cats; the veterinary nurses' pain scores were higher for all procedures than those of veterinary surgeons in a previous study. Both veterinary nurses and veterinary surgeons were primarily involved with monitoring pain postoperatively, and 96 per cent of veterinary nurses felt that their knowledge of pain management could be enhanced; 8.1 per cent of the practices used a formal pain scoring system, with the simple descriptive scale most commonly used; 80.3 per cent of the veterinary nurses agreed that a pain scale was a useful clinical tool.

The kinetic parameters of the limbs of 23 normal, client-owned cats were evaluated by encouraging them to walk and jump normally on a pressure-sensitive walkway. Each cat was encouraged to walk across the walkway five times over a period of 30 to 45 minutes (by using food, toys, the owner's presence and a purpose-built tunnel) at a target speed of 0.6 m/s (and an acceleration of less than +/- 0.1 m/s(2)). They were then encouraged to jump on to the walkway from a height of 1 m five times at five-minute intervals. The kinetic parameters of peak vertical force (PVF) and vertical impulse (VI) were measured for each limb (the forelimbs only for the jumps), and expressed as a percentage of bodyweight (PVF(%BW) and VI(%BW/S)). Fifteen of the 23 cats satisfactorily completed three to five walks and two to five jumps that could be analysed. There were no significant differences between the PVF or VI of the left and right limbs, but both parameters were significantly greater for the forelimbs than the hindlimbs (P<0.001) for the walking data. The mean (sd) PVF(%BW) for the forelimbs and hindlimbs were 48.2 (6.0) and 38.3 (4.0), respectively, and the mean VI(%BW/s) were 16.9 (3.2) and 13.3 (2.8). Jumping down generated significantly greater PVF (P<0.01) and slightly greater VI than during walking; there were no significant differences between the left and right forelimbs. The mean PVF(%BW) was 148.9 (16.4) and the mean VI(%BW/s) was 18.1 (4.3).

The mammary gland is a common site of neoplasms in the female cat. All the malignant tumors metastasize to a lesser or a greater extent through the lymphatic system. However, the anatomical knowledge of this system is not sufficiently well known in cats to develop a reasoned model for the extirpation of these glands in case of malignant tumors. A study of the lymph drainage in 50 female cats was done by indirect injection in vivo of India ink inside the mammary parenchyma. After a waiting interval, mammary glands were extracted and the thoracic cavity opened. All the lymph nodes were examined after clearing. The success rate of the colorations of lymph nodes and lymph vessels was 91.8%. Out of the 100 observed mammary chains, the two intermediate mammary glands (T2, A1) may drain caudally to the superficial inguinal lymph center and/or cranially to the axillary lymph center. The T1 gland always drains exclusively cranially and A2 exclusively caudally. The two mammary glands (T1 and A1) often drain towards the sternal cranial lymph nodes, but 100% of the T2 drain towards it. This research assumes that the limit between the two directions of drainage can exist only between glands T2 and A1. The results obtained with the study of the 1st, 2nd, 3rd, and 4th mammary glands permit production of new and more complete data of functional significance that will eventually aid block dissection surgical technique in the removal of malignant tumors in cats.

Thermal thresholds were measured in eight cats after the intramuscular administration of morphine (0.2 mg/kg), buprenorphine (0.01 mg/kg) or butorphanol (0.2 mg/kg), doses commonly used in clinical practice; 0.9 per cent saline (0.3 ml) was injected as a control. Groups of six cats were used and each cat participated in at least two treatments, according to a randomised design. The investigator was blinded to the treatments. The thermal thresholds were measured with a testing device developed specifically for cats, and measurements were made before and five, 30, 45 and 60 minutes and two, four, six, 12 and 24 hours after the injections. There was no significant change in thermal threshold after the injection of saline. With butorphanol, the threshold was increased only at five minutes after the injection and was decreased two hours after the injection; with morphine it was increased from between four and six hours after the injection, and with buprenorphine it was increased from between four and 12 hours after the injection.

The effect of the ultrasonic output of a commercial cat 'deterrent' was assessed by measuring the behaviour responses of 10 cats in a standard test arena. The cats were introduced to the arena approximately nine metres outside the stated range of efficacy of the product and small food piles were placed at one metre intervals towards the device. When the cats were released from the basket, their behaviour and location were recorded continuously. The behaviour of the cats with the device on and off was compared by using a general linear model and chi-squared analysis. Differences between individual cats were a significant factor in explaining the variance associated with the amount of 'relaxed behaviours' (P<0.001), and the time spent within the range of the device (P=0.006). The only significant behaviour changes recorded when the device was on, were an increased likelihood of ear flicking (P<0.001), less time spent actively exploring (P=0.043), and an increase in the amount of time spent in the reported ultrasonic range of the device (P=0.003).

Thirteen overweight domestic short-haired cats were fed a commercial low calorie diet for 18 weeks at an energy intake to lose weight; they lost an average of 18.1 per cent of their starting weight. An evaluation of their body composition by dual energy x-ray absorptiometry before and after the study suggested that most of the weight lost was composed of fat. The cats' lean bodyweight did not change significantly, but increased as a proportion of total bodyweight.

Recent studies have suggested that the mechanical properties of aponeurosis are not similar to the properties of external tendon. In the present study, the lengths of aponeurosis, tendon, and muscle fascicles were recorded individually, using piezoelectric crystals attached to the surface of each structure during isometric contractions in the cat soleus muscle. We used a surgical microscope to observe the surface of the aponeurosis, which revealed a confounding effect on measures of aponeurosis length due to sliding of a thin layer of epimysium over the proximal aponeurosis. After correcting for this artifact, the stiffness computed for aponeurosis was similar to tendon, with both increasing from around 8 F0/Lc (F0 is maximum isometric force and Lc is tissue length) at 0.1 F0 to 30 F0/Lc at forces greater than 0.4 F0. At low force levels only (0.1 F0), aponeurotic stiffness increased somewhat as fascicle length increased. There was a gradient in the thickness of the aponeurosis along its length: its thickness was minimal at the proximal end and maximal at the distal end, where it converged to form the external tendon. This gradient in thickness appeared to match the gradient in tension transmitted along this structure. We conclude that the specific mechanical properties of aponeurosis are similar to those of tendon.

Combinations of acepromazine maleate, pethidine hydrochloride and atropine sulphate (0.05 mg/kg) or acepromazine maleate and pethidine hydrochloride and acepromazine maleate alone or atropine sulphate (0.1 mg/kg) alone were used to premedicate cats before they were anaesthetised with thiopentone, to investigate their effects on gastric pressure, lower oesophageal sphincter pressure and barrier pressure under anaesthesia. Manometric measurements were made by using a non-perfused manometric technique. The lower oesophageal sphincter pressure was lowest in the cats premedicated with atropine sulphate alone. The difference in barrier pressure between the atropine (0.1 mg/kg) and acepromazine treated cats was highly significant. The risk of gastro-oesophageal reflux appeared to be highest with atropine (0.1 mg/kg) if barrier pressure is used as an indicator of the likelihood of reflux.

The anaesthetic induction agents thiopentone, propofol and alphaxalone-alphadolone were administered to cats intravenously and ketamine and xylazine-ketamine-atropine were administered intramuscularly in order to determine their effects on gastric pressure, lower oesophageal sphincter pressure, and barrier pressure. Manometric measurements were made with a non-perfused catheter tip pressure transducer. All the anaesthetic induction agents decreased the tone of the lower oesophageal sphincter but the reduction was least with ketamine. Lower oesophageal sphincter tone was significantly higher in cats anaesthetised with either xylazine-ketamine-atropine or propofol than in cats anaesthetised with either thiopentone or alphaxalone-alphadolone. Despite a higher gastric pressure in the cats anaesthetised with ketamine rather than with the other drugs except propofol, the barrier pressure was also significantly higher in cats anaesthetised with ketamine than in cats anaesthetised with any of the other drugs except xylazine-ketamine-atropine. The risk of gastrooesophageal reflux seemed to be higher with alphaxalone-alphadolone than with thiopentone if the lower oesophageal sphincter pressure and gastric pressure are used as indicators of likely reflux.

The anaesthesia induced by cyclohexylamine derivatives in cats was studied by comparing the effects induced by four pairs of agents: acepromazine/ketamine, xylazine/ketamine, zolazepam/tiletamine and medetomidine/ketamine. Acepromazine/ketamine was free of undesirable side effects but provided inadequate anaesthetic cover. The other combinations differed only in the dosage, the quality of the anaesthesia and the importance of the side effects. Medetomidine/ketamine was the best combination; it induced a good degree of anaesthesia with small doses and was free of major side effects.

Several muscles of the cat hindlimb, including biceps femoris and tenuissimus, are composed of short, in-series muscle fibers with tapered intrafascicular terminations. Tension generation and transmission within such muscles requires that active fibers should be mechanically coupled in series via myomyous junctions, specialized connective tissue attachments, or the endomysium. This report establishes that the tapered fibers of the cat biceps femoris and tenuissimus muscles have insignificant numbers of either myomyous or specialized connective tissue junctions. Tension appears to be transmitted in a distributed manner across the plasmalemma of the tapered (and probably the non-tapered) portions of the fibers to the connective tissue of the endomysium, which is therefore an essential series elastic element in these muscles. Subplasmalemmal dense plaques were identified and may play a role in transmembrane force transmission. In addition to the endomysium, passive muscle fibers may also serve to transmit tension between active fibers, and therefore should also be considered to be series elastic elements.

The pyramidal motor system underwent dramatic phylogenetic developments. Ethologically, this has found expression in higher capacities for accurate movements. An hypothesis and supporting data are offered that this depends on the advancement in the higher species of a system based on the attainment of higher accuracy by an increase in the number of channels, an increased range of conduction velocity values, an increase in surround effects of the PTN and the evolvement of a stochastically based mechanism the accuracy of operation of which depends at least on the above-mentioned factors.

The Chiltern Box is a small electrocardiograph designed for home monitoring of human patients. Its veterinary application has been investigated in the dog, the cat and the horse. It has been useful in the diagnosis of previously undiagnosed dysrhythmias in dogs showing signs of exercise intolerance and syncope.

1 The cat anococcygeus muscle is shown to possess a dual innervation similar to the rat anococcygeus, with a motor adrenergic innervation and an inhibitory innervation whose transmitter is unknown. The pharmacological properties of the cat muscle were investigated and compared with those of the rat muscle.2 The cat muscle contracts to noradrenaline, 5-hydroxytryptamine, tyramine, amphetamine, guanethidine, cocaine and lysergic acid diethylamide (LSD). The effects of noradrenaline and 5-hydroxytryptamine are blocked by phentolamine and methysergide respectively.3 The cat anococcygeus is relaxed by acetylcholine, carbachol, isoprenaline, ATP, prostaglandins E(1), E(2) and F(2alpha) and vasopressin, all of which contract the rat muscle. The effects of acetylcholine and carbachol are blocked by atropine and those of isoprenaline by propranolol.4 Field stimulation produces contraction of the cat anococcygeus, which is blocked by phentolamine and guanethidine but unaffected by hexamethonium, atropine or neostigmine.5 In the presence of guanethidine (10(-5)M), the tone of the muscle is raised and field stimulation produces relaxation of the muscle. These inhibitory responses are unaffected by phentolamine, hexamethonium, atropine or neostigmine.6 Neostigmine potentiates the effects of acetylcholine, but not of carbachol in relaxing the cat anococcygeus and in contracting the rat anococcygeus, but has no effect on either motor or inhibitory responses to field stimulation.7 Cold storage for up to eight days had little effect on either the motor response to noradrenaline or the motor or inhibitory response to field stimulation of the cat anococcygeus. Beyond eight days, the response to field stimulation diminishes more rapidly than the response to noradrenaline.

In anaesthetized cats, stimulation of the vagus nerves produced bradycardia and a bronchoconstriction which was measured as an increase in lung resistance (RL) and a fall in dynamic lung compliance (Cdyn); these effects were abolished by atropine. Gallamine potentiated vagally-mediated changes in RL and Cdyn at doses that blocked muscarinic receptors in the heart and inhibited neuromuscular transmission. (+)-Tubocurarine and suxamethonium did not affect the response of the lung or the heart to vagal stimulation. Bronchoconstriction induced by intravenous acetylcholine was not potentiated by gallamine, indicating that postsynaptic muscarinic receptors in the lung and changes in muscle tone were not involved. Potentiation of vagally-induced bronchoconstriction appears to be due to blockade of inhibitory muscarinic receptors located in the pulmonary parasympathetic nerves innervating both central and peripheral airways. Pilocarpine was an agonist for these neuronal receptors as it inhibited vagally-induced bronchoconstriction at low doses (10 ng to 1 microgram kg-1). The results demonstrate that gallamine is an antagonist and pilocarpine an agonist at neuronal muscarinic receptors which attenuate parasympathetic nerve activity in feline lung.