title: Neurogenic and non-neurogenic responses in the urinary bladder of hibernating hamster.
abstract: 1. Purinergic and cholinergic components of parasympathetic neurotransmission and contractile responses to exogenous alpha,beta-methylene ATP, acetylcholine, substance K, substance P, calcitonin gene-related peptide, vasoactive intestinal polypeptide and capsaicin have been investigated in the urinary bladder of hibernating hamsters (4 weeks), cold exposed (4 weeks) and age-matched controls. 2. Electrical field stimulation (EFS) evoked increased frequency-dependent contractions in the detrusor strips from hibernating hamsters compared with those obtained from cold-exposed and age-matched animals. Tetrodotoxin (10(-6) M) completely blocked the frequency-dependent contractions in all groups. 3. The purinergic component of the parasympathetic neurotransmission was not affected in hibernating and cold-exposed animals while the cholinergic component was increased with respect to age-matched animals. The neurogenic response to EFS, still present after incubation with atropine (10(-6) M) and suramin (10(-4) M), was attenuated by indomethacin (10(-6) M) and blocked by tetrodotoxin (10(-6) M). 4. Exogenous administration of alpha,beta-methylene ATP elicited a significantly reduced contraction in strips from hibernating and cold-exposed hamsters relative to age-matched animals. The contractile response to exogenous acetylcholine was greater in the detrusors from hibernating hamsters than in cold-exposed and age-matched animals. Substance K elicited reduced contractions in preparations from hibernating animals compared with cold-exposed and control animals. Calcitonin gene-related peptide, vasoactive intestinal polypeptide, substance P and capsaicin did not elicit any relaxant or contractile response either at resting tone or in carbachol (5 x 10(-7) M)-precontracted tissues. 5. In summary, our findings indicate that 4 weeks of hibernation can significantly increase neurogenic responses in the hamster urinary bladder. This appears to be due to an increase in postjunctional responses to acetylcholine. In contrast, there was a decrease of the postjunctional responses to the parasympathetic cotransmitter ATP and also to the sensory-motor neurotransmitter substance K.
authors.affiliation: Department of Anatomy and Developmental Biology and Centre for Neuroscience, University College London.
authors.forename: C
authors.initials: C
authors.lastname: Pinna
authors.forename: G E
authors.initials: GE
authors.lastname: Knight
authors.forename: L
authors.initials: L
authors.lastname: Puglisi
authors.forename: G
authors.initials: G
authors.lastname: Burnstock
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology; D006224:Cricetinae; D004558:Electric Stimulation; D006605:Hibernation; D008297:Male; D008647:Mesocricetus; D015288:Neurokinin A / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects; D001743:Urinary Bladder / Q000187:drug effects / Q000294:innervation / Q000502:physiology*; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology
chemical_list: D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D015288:Neurokinin A; D000255:Adenosine Triphosphate; D015740:Calcitonin Gene-Related Peptide; D000109:Acetylcholine; C002630:alpha,beta-methyleneadenosine 5'-triphosphate