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Experimental Physiology Jan 2009Adenosine 5'-triphosphate (ATP) is a cotransmitter with classical transmitters in most nerves in the peripheral and central nervous systems, although the proportions...
Adenosine 5'-triphosphate (ATP) is a cotransmitter with classical transmitters in most nerves in the peripheral and central nervous systems, although the proportions vary between tissues and species and in different developmental and pathophysiological circumstances. There was early evidence that ATP was released together with acetylcholine (ACh) from motor nerves supplying skeletal muscle, although it was considered at the time as a molecule involved in the vesicular uptake and storage of ACh. Later it was shown that in the developing neuromuscular junction, released ATP acted on P2X receptor ion channels as a genuine cotransmitter with ACh. Adenosine triphosphate was shown to be released from sympathetic nerves supplying the guinea-pig taenia coli in 1971. Soon after, the possibility was raised that ATP was coreleased with noradrenaline from sympathetic nerves to guinea-pig seminal vesicle, cat nictitating membrane and guinea-pig vas deferens. Sympathetic purinergic cotransmission has also been demonstrated in many blood vessels. Parasympathetic nerves supplying the urinary bladder use ACh and ATP as cotransmitters; ATP acts through P2X ionotropic receptors, whereas the slower component of the response is mediated by the metabotropic muscarinic receptor. Adenosine triphosphate and glutamate appear to be cotransmitters in primary afferent sensory neurons. Adenosine triphosphate, calcitonin gene-related peptide and substance P coexist in some sensory-motor nerves. A subpopulation of intramural enteric nerves provides non-adrenergic, non-cholinergic inhibitory innervation of gut smooth muscle. Three cotransmitters are involved, namely ATP, nitric oxide and vasoactive intestinal polypeptide. In recent years, studies have shown that ATP is released with ACh, noradrenaline, glutamate, gamma-aminobutyric acid, 5-hyroxytryptamine and dopamine in different subpopulations of neurons in the central nervous system.
Topics: Acetylcholine; Adenosine Triphosphate; Animals; Central Nervous System; Glutamic Acid; Humans; Neurotransmitter Agents; Nitric Oxide; Norepinephrine; Peripheral Nervous System; Purines; Receptors, Purinergic P2; Receptors, Purinergic P2X; Synaptic Transmission; Vasoactive Intestinal Peptide
PubMed: 18723580
DOI: 10.1113/expphysiol.2008.043620 -
Animals : An Open Access Journal From... Nov 2023There has, to date, been no systematic study of the various ways in which birds blink. Digital video recordings were made, and studied using still frames, of 524 bird...
There has, to date, been no systematic study of the various ways in which birds blink. Digital video recordings were made, and studied using still frames, of 524 bird species, mainly in zoos but also in the wild. Videos on 106 species from various sites on the internet were studied, some of which we had also videoed, giving a total of 591 (out of a possible 10,000) species from all 43 orders and 125 (out of a possible 249) families. Digital video recordings were also made of 15 (out of a possible 24) species of crocodile. Three types of blink were observed in birds: (1) Nictitating membrane blinks were rapid and brief (phasic) and occurred mainly on head movement. (2) Upper lid blinks were seen in parrots, owls, pigeons and some others. These were also rapid and brief and accompanied nictitating membrane blinks. (3) Lower lid blinks were slow and sustained (tonic) and occurred with drowsiness and preening. Nictitating membrane blinks and lower lid blinks were seen in crocodiles but not upper lid blinks. Globe retraction, where the eyeball is pulled into the orbit of the skull during a blink, was seen in crocodiles but not birds. Phasic blinks remove debris and moisten the cornea, essential for allowing oxygen to diffuse into the cornea, which has no blood supply. Tonic blinks are probably mainly protective. The orders of birds which have upper lid blinking are not closely related and this feature is probably the result of convergent evolution.
PubMed: 38067009
DOI: 10.3390/ani13233656 -
Veterinary Medicine and Science Sep 2022The present report characterises a spontaneous nictitating membrane abnormality in a Japanese white rabbit.
OBJECTIVE
The present report characterises a spontaneous nictitating membrane abnormality in a Japanese white rabbit.
ANIMAL STUDIED
The animal was a male Japanese white rabbit (Oryctolagus cuniculus, Kbs:JW, 10 weeks old at the time of purchase) that had not received any treatment. A morphological abnormality of the nictitating membrane in the animal's right eye was detected.
PROCEDURES
Ophthalmological examinations, including slit-lamp biomicroscopy, corneal and conjunctival staining with fluorescein and lissamine green, fundoscopy, blinking rate measurement, Schirmer's tear test, and tonometry were performed. The animal was euthanised at 15 weeks of age, and histopathological examinations of the abnormal nictitating membrane, palpebral conjunctiva, eyelid and eyeball were performed.
RESULTS
The tip of the nictitating membrane adhered to the palpebral conjunctiva of the medial canthus. The eye and periocular tissues showed no abnormalities in the ophthalmological examinations, except for the structure of the nictitating membrane. Histopathological examination revealed that the adhered site of the nictitating membrane and the palpebral conjunctiva consisted of dense fibrous connective tissue that was consecutive to the conjunctiva adjacent to the eyelid margin and lamina propria of the nictitating membrane. The fibrous connective tissue was covered with stratified squamous epithelium.
CONCLUSION
Based on these results, we diagnosed this abnormal finding as congenital nictitating membrane dysplasia. This paper is the first case report describing a congenital structural abnormality of the nictitating membrane in a Japanese white rabbit.
Topics: Animals; Conjunctiva; Fluorescein; Japan; Male; Nictitating Membrane; Rabbits
PubMed: 35588501
DOI: 10.1002/vms3.844 -
Frontiers in Behavioral Neuroscience 2022For almost a century the classical conditioning of nictitating membrane/eyelid responses has been used as an excellent and feasible experimental model to study how the... (Review)
Review
For almost a century the classical conditioning of nictitating membrane/eyelid responses has been used as an excellent and feasible experimental model to study how the brain organizes the acquisition, storage, and retrieval of new motor abilities in alert behaving mammals, including humans. Lesional, pharmacological, and electrophysiological approaches, and more recently, genetically manipulated animals have shown the involvement of numerous brain areas in this apparently simple example of associative learning. In this regard, the cerebellum (both cortex and nuclei) has received particular attention as a putative site for the acquisition and storage of eyelid conditioned responses, a proposal not fully accepted by all researchers. Indeed, the acquisition of this type of learning implies the activation of many neural processes dealing with the sensorimotor integration and the kinematics of the acquired ability, as well as with the attentional and cognitive aspects also involved in this process. Here, we address specifically the functional roles of three brain structures (red nucleus, cerebellar interpositus nucleus, and motor cortex) mainly involved in the acquisition and performance of eyelid conditioned responses and three other brain structures (hippocampus, medial prefrontal cortex, and claustrum) related to non-motor aspects of the acquisition process. The main conclusion is that the acquisition of this motor ability results from the contribution of many cortical and subcortical brain structures each one involved in specific (motor and cognitive) aspects of the learning process.
PubMed: 36570703
DOI: 10.3389/fnbeh.2022.1057251 -
Open Veterinary Journal 2022Canine non-infectious deep ulcerative keratitis is considered a severe ocular disorder that possibly can progress to perforation. Immediate treatment should be directed...
Comparative study of healing time of canine non-infectious deep ulcerative keratitis between medical therapy alone and combined treatment with medical therapy and a nictitating membrane flap: A retrospective study.
BACKGROUND
Canine non-infectious deep ulcerative keratitis is considered a severe ocular disorder that possibly can progress to perforation. Immediate treatment should be directed to stimulate corneal wound healing, control infection, and minimize self-trauma while eliminating the underlying causes.
AIM
This retrospective study was aimed to compare the difference in non-infectious deep corneal wound healing time between cases treated with medical therapy alone and those treated with medical therapy combined with a nictitating membrane flap.
METHODS
The medical records at the Ophthalmology Clinic, Small Animal Teaching Hospital, Faculty of Veterinary Science, Chulalongkorn University between January 2018 and March 2020 were retrospectively reviewed. Sixty-six eyes (from 65 dogs) diagnosed with non-infectious deep ulcerative keratitis from the medical treatment group ( = 34) and the combined treatment group ( = 32) were included. The combined treatment group was prescribed the same conservative medical administrations plus a surgical nictitating membrane flap for 14 days.
RESULTS
Healing time was defined as the duration of time from the day that the dog had been diagnosed with deep ulcerative keratitis by a fluorescein staining test to the day that the corneal fluorescein stain was negative. Overall, the mean age of dogs with deep ulcerative keratitis was 10.49 ± 4.7 years. The disease was commonly evident in females more than males. Shih Tzu was the most prevalent dog breed. The corneal healing time between dogs receiving medical therapy alone and those receiving combined treatment was not statistically significant ( = 0.386). Healing times were not significantly different between sex and breed ( = 0.41). The median corneal healing time for dogs older than 10 years in the combined treatments group (29.5 days; ranging from 20 to 46 days) was longer than for those receiving medical therapy alone (21 days; ranging from 9.5 to 30.5 days).
CONCLUSION
Supportive therapy including a nictitating membrane flap is suggested in dogs prone to deep corneal ulcers not involving infection. Even though the healing time is not statistically significant, a nictitating membrane flap acts as a tissue bandage to reduce friction over the cornea, and it also alleviates the healing process by moistening the ocular surface.
Topics: Male; Female; Dogs; Animals; Corneal Ulcer; Retrospective Studies; Nictitating Membrane; Wound Healing; Fluoresceins; Dog Diseases
PubMed: 36650856
DOI: 10.5455/OVJ.2022.v12.i6.5 -
Journal of Feline Medicine and Surgery Feb 2022Described are four cats diagnosed with ophthalmomyiasis externa caused by larvae. Medical records were retrospectively reviewed to identify cats with ophthalmomyiasis...
CASE SERIES SUMMARY
Described are four cats diagnosed with ophthalmomyiasis externa caused by larvae. Medical records were retrospectively reviewed to identify cats with ophthalmomyiasis externa between 2005 and 2020 at Cornell University Hospital for Animals. Signalment, history, clinical and diagnostic findings, treatment and outcome were recorded. All cats were young (< 3 years of age), had outdoor access and were initially examined during the summer months. All cases had unilateral disease with the right eye affected. Two cases had nictitating membrane lesions and two had orbital disease. Concurrent superficial corneal ulceration was present in three cats. Two cats suffered from pyrexia, suspected secondary to inflammation from the larval infestation. Successful larval removal was performed in all cats, which resulted in improvement of discomfort and clinical signs. A corneal ulcer persisted in one cat, which was lost to follow-up prior to ulcer resolution. Parasite identification confirmed species infestation in all cases.
RELEVANCE AND NOVEL INFORMATION
To the authors' knowledge, this is the first report of feline ophthalmomyiasis externa caused by species. Parasite removal was successful in restoring comfort and resolving clinical signs in all cats with adequate follow-up information.
Topics: Animals; Cat Diseases; Cats; Diptera; Eye Infections, Parasitic; Larva; Myiasis; Retrospective Studies
PubMed: 33988048
DOI: 10.1177/1098612X211013021 -
Integrative Organismal Biology (Oxford,... 2020The ultrastructure of the nictitating membrane in the little penguin was studied using both scanning and transmission electron microscopy to improve our understanding...
The ultrastructure of the nictitating membrane in the little penguin was studied using both scanning and transmission electron microscopy to improve our understanding of the function of ocular adnexa in diving birds. Following euthanasia, eyes were enucleated and immersion fixed in Karnovsky's fixative. The nictitating membrane and conjunctiva were embedded in araldite and semi- or ultra-thin sections were stained and photographed using compound and transmission electron microscopes, respectively. Ultrastructural dimensions were measured directly from digital photographs. Surface ultrastructure was examined using scanning electron microscopy. The transparent nictitating membrane consists of a dense stroma surrounded by epithelia on both the external (conjunctival) and internal (bulbar) surfaces. The conjunctival surface of the membrane near the leading edge is covered by microvilli, which transition to microplicae and finally to microridges in the periphery. Beneath the epithelial cells, there is a well-developed basement membrane. Scattered throughout this epithelium are a few goblet cells. The surface of the bulbar epithelium is covered by microvilli near the leading edge, which become denser peripherally. The stroma consists of densely-packed collagen fibrils, which are randomly oriented in bundles near the leading edge but are aligned in the same direction parallel with the epithelial and corneal surfaces and with the leading edge, when the membrane is extended. The ultrastructure of the nictitating membrane in the little penguin differs from other birds and its function is predominantly protective, while preserving clear vision in both water and air.
PubMed: 33791581
DOI: 10.1093/iob/obaa048 -
British Journal of Pharmacology and... Dec 1959The actions of 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP) have been studied to discover under what conditions a blocking action could be seen....
The actions of 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP) have been studied to discover under what conditions a blocking action could be seen. Dimethylphenylpiperazinium has a stimulant action on autonomic ganglia, stimulating the superior cervical ganglion and causing contraction of the nictitating membrane. It caused slowing followed by acceleration of the rate of beat of isolated rabbit atria. The denervated gastrocnemius muscle contracted if dimethylphenylpiperazinium was injected intra-arterially. Under other circumstances a blocking action was seen. It blocked peristalsis in the isolated guinea-pig ileum stimulated by raising intraluminal pressure and inhibited the response of the rat diaphragm and of the cat gastrocnemius stimulated through the motor nerve. It is suggested that dimethylphenylpiperazinium acts by depolarization, causing stimulation of resting muscle but inhibition by prolonging depolarization.
Topics: Animals; Cats; Dimethylphenylpiperazinium Iodide; Ganglia, Autonomic; Guinea Pigs; Ileum; Nictitating Membrane; Piperazines; Rabbits; Rats
PubMed: 14417244
DOI: 10.1111/j.1476-5381.1959.tb00957.x -
PloS One 2018We evaluated the feasibility and safety of nictitating membrane fixation to address reduced contact lens stability by the nictitating membrane in a rabbit model. Under...
We evaluated the feasibility and safety of nictitating membrane fixation to address reduced contact lens stability by the nictitating membrane in a rabbit model. Under general anesthesia, twelve animals received a horizontal mattress suture between the nictitating membrane and the upper eyelid of one eye. To assess the effects of this technique and secondary side effects, contact lens stability test, Schirmer tear test, tear break-up time measurement, eye tissue pathology and morphology were evaluated. Contact lens stability was increased after nictitating membrane fixation. The percentage of contact lens retention in the nictitating membrane fixed rabbit after 4 hours was 90% whereas that in the untreated rabbit was 42.5%. In addition, there were no significant differences in tear quantity and quality between the fixed and untreated eyes. Furthermore, no remarkable pathological lesions were found in gross observation during the 1-month time period or the following pathological examination. In this study, we demonstrated that nictitating membrane fixation increases contact lens stability without specific side effects using a rabbit model. This minimally invasive procedure could be useful when designing animal models for testing new contact lenses and has potential to apply to other biomaterial research on the ocular surface.
Topics: Animals; Conjunctiva; Contact Lenses, Hydrophilic; Cornea; Feasibility Studies; Male; Models, Animal; Nictitating Membrane; Polyglactin 910; Rabbits; Tears
PubMed: 29584737
DOI: 10.1371/journal.pone.0194795 -
The Journal of Neuroscience : the... Jan 1989Unilateral cerebellar lesions abolished the occurrence of ipsilateral conditioned nictitating membrane responses during the 285 msec interval between onset of the...
Unilateral cerebellar lesions abolished the occurrence of ipsilateral conditioned nictitating membrane responses during the 285 msec interval between onset of the conditioned and unconditioned stimuli on paired trials. This effect was obtained in 15 animals sustaining damage to the dorsolateral aspects of the interpositus nucleus and the adjoining white matter. However, conditioned responses did occur during the 800 msec observation interval employed on tone-alone test trials, and these responses exhibited the classic performance deficits normally associated with cerebellar damage: a low frequency of occurrence (14%, as compared with 96% before the lesion); a 3.1 mm decrease in amplitude; a 236 msec increase in onset latency; a 563 msec increase in latency of peak amplitude; and a 327 msec increase in rise time. Four of the 15 animals failed to demonstrate greater than 5% responding during the test trials. These performance deficits were not specific to the learned, conditioned response. Unconditioned responses were also reduced in frequency and increased in latency of peak amplitude and rise time, especially when elicited at lower air-puff intensities. These deficits in the unconditioned response were observed in animals that failed to exhibit conditioned responses on either paired or test trials, as well as in animals demonstrating conditioned responses only during test trials. We conclude that the cerebellum has a general role in regulating the nictitating membrane reflex so that deficits in learned responses observed after cerebellar lesions are secondary to a broader deficit in performance. The performance deficits appear to consist of a sensory component, as reflected by an increase in stimulus threshold for elicitation of the nictitating membrane reflex, and a motor component, as reflected by the altered topography of the evoked response. The results of this study thus reaffirm the role of the cerebellum in regulating the sensorimotor processes necessary for the optimal performance of both conditioned and unconditioned responses and extends this role to the expression of a simple cranial nerve reflex.
Topics: Animals; Cerebellum; Conditioning, Psychological; Female; Learning; Male; Nictitating Membrane; Rabbits; Reflex
PubMed: 2913208
DOI: 10.1523/JNEUROSCI.09-01-00299.1989